Method of reducing the risk of embolization of peripheral blood vessels

ABSTRACT

A method of reducing the risk of embolization of peripheral blood vessels by providing a medical device having an expandable member having a drug coating layer which has a crystalline morphological form including a plurality of crystal particles of a water-insoluble drug regularly arranged and uniformly sized on the surface of the medical device, inserting the medical device in peripheral blood vessels, expanding the expandable member, pressing the drug coating layer to a blood vessel wall such that at least part of the plurality of crystal particles are transferred to the blood vessel wall, and deflating the expandable member such that the generation of microparticulates having a size that causes embolization of peripheral blood vessels is suppressed.

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/321,282, filed on Jul. 1, 2014, which claims the benefit of U.S.Provisional Application Nos. 61/994,652, 61/994,589 and 61/994,467, allfiled on May 16, 2014, the contents of which are hereby incorporated byreference.

TECHNICAL FIELD

Disclosed is a drug coating layer of water-insoluble drugs, and a drugcoating layer exhibiting a specific crystalline morphological form ofthe water-insoluble drugs, and a method of reducing the risk ofembolization of peripheral blood vessels.

BACKGROUND DISCUSSION

In recent years, development of a drug eluting balloon (DEB) in which aballoon catheter is coated with drugs has been actively performed, andit has been reported to be effective in the treatment and prevention ofrestenosis. The balloon is coated by a coating film including drugs andexcipients, and when a blood vessel is dilated, the balloon pressesagainst a blood vessel wall, and it delivers the drugs to target tissue.

In recent years, it has been found that a morphological form of thedrugs coated on the balloon surface influences releasing property andtissue transferability of drugs from the balloon surface in a lesionaffected area, and it is known that control of the crystal form oramorphous form of drugs is important.

Since it cannot be said that the drug eluting balloon having a coatinglayer in the related art sufficiently exhibits low toxicity and a higheffect on a stenosis inhibition rate when treating a stenosis portion ina blood vessel, a medical device of which the toxicity is even lower andthe stenosis inhibiting effect is high is desired.

DEB has an advantage of use because DEB does not leave any foreignbodies in the blood vessels, unlike BMS (bare metal stent) and DES(drug-eluting stent). In particular, although use of stents is notrecommended in the treatment of lower limbs, a demand for DEB isrequired. Meanwhile, a risk for the embolization of downstreamperipheral blood vessels is feared which is caused by microparticulatesupon use of DEB. Since embolization of peripheral blood vessels couldcause a risk of amputation of lower limbs due to necrosis, alleviationof embolization of peripheral blood vessels is clinically significant.The blood vessels in the BTK (below-the-knee) area are positioned to theperipheral, and the diameter of the blood vessels is small. Therefore arisk for the embolization is focused on and DEB is required to have alower risk of the embolization. It is presumed that this is relevant notonly to the number of the microparticulates, but also the size ofmicroparticulates. The larger the size is, the more possibility themicroparticulates are distributed in the muscles adjacent downstreamperipheral blood vessels. It is thought that this raises the risk of theembolization, and the size of the microparticulates is expected to besmall.

To obtain sufficient treatment effects of DEB, it is important to keepthe drug concentration to be transferred to the lesion of the vasculartissue and chronological transition of drug concentration. Further, inthe initial term to inhibit the proliferation of smooth muscle cells,relatively high drug concentration is necessary in the vascular tissue,although in the final term to non-inhibit endothelial cells growth,prompt clearance of drug from the tissue is required. When these twopoints are achieved by DEB in terms of a change of drug concentration,DEB can provide superior treatment effects in both efficacy and safety.

One of the features of DEB is to immediately release drug upon thedilation of the balloon in a couple of minutes and to transfer asufficient amount of the drug to the vascular tissue. If the drug is nottransferred uniformly to the entire treated lesion, uniform inhibitoryeffects cannot be expected to be imparted to the lesion under treatment.Particularly, since the length of lesion in the blood vessels of lowerlimbs is longer than that of coronary arteries, it is difficult toobtain uniform efficacy in lower limbs.

SUMMARY

A challenge in the art is to provide a drug coating layer having amorphological form of water-insoluble drugs of which the intravascularstenosis inhibitory effect in a lesion affected area is high, whendelivering medical device coated with a drug into the body and medicaldevice using the same.

The challenge is addressed by a drug coating layer having a specificcrystalline morphological form of a water-insoluble drug which has ahigh intravascular stenosis inhibitory effect in a lesion affected area.

Various aspects are disclosed as follows:

(1) A drug coating layer which has a morphological form including aplurality of elongated bodies with long axes that each crystal of awater-insoluble drug independently has, on a substrate surface, in whichthe long axes of the elongated bodies are nearly linear in shape, andthe long axes of the elongated bodies form an angle in a predeterminedrange, preferably an angle in a range of 45° to 135°, with respect to asubstrate plane with which the long axis of the elongated bodyintersects.

(2) The drug coating layer described in (1) in which at least near thedistal of the elongated body is hollow.

(3) The drug coating layer described in (1) or (2) in which across-sectional shape of the elongated body on a surface perpendicularto the long axis is a polygon.

(4) The drug coating layer which is a drug coating layer in whichcrystals of a flatly elongated hair-like shape of crystals of thewater-insoluble drug are randomly laminated on the substrate surface,and in which the long axes of some of the crystals have a portion curvedin shape, and crystals having other shapes are not mixed in the samecrystal plane.

(5) The drug coating layer described in (4) in which the surface of thecrystal of the water-insoluble drug is covered with an amorphous film.

(6) The drug coating layer including a crystalline morphological form ofthe water-insoluble drug, crystal particles of the water-insoluble drugarranged with regularity on the substrate surface, and excipientparticles formed of an excipient irregularly arranged between thecrystal particles, wherein a molecular weight of the excipient is lessthan a molecular weight of the water-insoluble drug, a ratio occupied bythe excipient particles per a predetermined area of the substrate isless than a ratio occupied by the crystal particles, and the excipientparticles do not form a matrix.

(7) The drug coating layer described in any one of (1) to (6) in whichthe water-insoluble drug is rapamycin, paclitaxel, docetaxel, oreverolimus.

(8) Medical device having the drug coating layer described in any one of(1) to (7) on the surface of the medical device, which is reduced indiameter to be delivered when delivered into a body, and enlarged indiameter to release a drug from the drug coating layer at an affectedpart.

(9) A method for delivering a drug having a step of delivering themedical device described in (8) to a lumen, a step of radially dilatinga dilatable portion provided in the medical device, and a step in whichthe drug coating layer which has the dilatable portion is applied to thelumen.

A drug coating layer for drug eluting medical device can be provided ofwhich the intravascular stenosis inhibitory effect in a lesion affectedarea is high and/or the toxicity is low.

A method is provided for reducing the risk of embolization of peripheralblood vessels, comprising providing a medical device having anexpandable member having a drug coating layer which has a crystallinemorphological form including a plurality of crystal particles of awater-insoluble drug regularly arranged and uniformly sized on thesurface of the medical device, inserting the medical device inperipheral blood vessels, expanding the expandable member, pressing thedrug coating layer to the blood vessel wall such that at least part ofthe plurality of crystal particles are transferred to the blood vesselwall, and deflating the expandable member such that the generationmicroparticulates having a size that causes embolization of peripheralblood vessels is suppressed.

A method is provided for treating peripheral artery diseases in lowerlimbs, comprising providing a medical device having an expandable memberhaving a drug coating layer which has a crystalline morphological formincluding a plurality of crystal particles of a water-insoluble drugregularly arranged and uniformly sized on the surface of the medicaldevice, inserting the medical device in peripheral blood vessels,expanding the expandable member, pressing the drug coating layer to theblood vessel wall such that at least part of the plurality of crystalsare transferred to the blood vessel wall, and deflating the expandablemember such that a pharmacokinetics profile is presented in which a drugconcentration in the blood vessels is kept for the inhibition of smoothmuscle cell proliferation in a high drug-concentration period of time,and for the non-inhibition of endothelial cell growth in a later lowdrug-concentration period of time.

A method is provided for inhibiting thickening of vascular intima,comprising providing a medical device having an expandable member havinga drug coating layer which has a crystalline morphological formincluding a plurality of crystal particles of a water-insoluble drugregularly arranged and uniformly sized on the surface of the medicaldevice, inserting the medical device in peripheral blood vessels,expanding the expandable member, pressing the drug coating layer to ablood vessel wall such that at least part of the plurality of crystalsare transferred to the blood vessel wall, and deflating the expandablemember such that a vascular intima thickening is inhibited uniformly inan entire treated lesion (entire long lesion) of stenosis to uniformlycause patency of the lesion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A to 1D are diagrams showing a scanning electron microscopicimage (hereinafter, referred to as SEM) of a surface of a drug coatinglayer prepared in Example 1. FIG. 1A is a SEM image at 2,000 timesmagnification of crystals observed on a substrate surface of the drugcoating layer prepared in Example 1. FIG. 1B is a SEM image at 1,000times magnification of crystals observed on another portion of asubstrate surface prepared in Example 1. FIG. 1C is a SEM image at 400times magnification of crystals observed on another portion of thesubstrate surface prepared in Example 1. FIG. 1D is a SEM image at 4,000times magnification of crystals observed at a cross-sectionperpendicular to the substrate surface of the drug coating layerprepared in Example 1.

FIG. 2 is a diagram showing a SEM image at 2,000 times magnification ofcrystals observed on the substrate surface of the drug coating layerprepared in Example 2.

FIG. 3A is a diagram showing a SEM image at 2,000 times magnification ofcrystals observed on the substrate surface of the drug coating layerprepared in Example 3. FIG. 3B is a SEM image at 4,000 timesmagnification of crystals observed at a cross-section perpendicular tothe substrate surface of the drug coating layer prepared in Example 3.

FIG. 4 is a diagram showing a SEM image at 2,000 times magnification ofcrystals observed on the substrate surface of the drug coating layerprepared in Example 4.

FIG. 5 is a diagram showing a SEM image at 2,000 times magnification ofcrystals observed on the substrate surface of the drug coating layerprepared in Example 5.

FIG. 6A is a diagram showing a SEM image at 2,000 times magnification ofcrystals observed on the substrate surface of the drug coating layerprepared in Example 6. FIG. 6B is a diagram showing a SEM image at 400times magnification of crystals observed on another portion of thesubstrate surface of the drug coating layer prepared in Example 6.

FIG. 7 is a diagram showing a SEM image at 2,000 times magnification ofcrystals observed on the substrate surface of the drug coating layer ofa commercially available drug eluting balloon (IN.PACT) manufactured byINVAtec JAPAN in Comparative Example 1.

FIG. 8 is a graph of an intravascular stenosis rate (%) showing aninhibitory effect on an intravascular stenosis in a pig coronary artery.

FIGS. 9A and 9B are graphs showing the particulate ratios of particlesize 10-25 μm and 100-900 μm, respectively, of Example 7 and ComparativeExample 3.

FIG. 10 is a graph showing the AUC of the drug on 0.02-0.04 day (0.5-1hour) to 7 day of Example 9 and of Comparative Examples C6 to C9 for thetransfer in the porcine femoral arterial tissue.

FIG. 11 is a graph showing the pharmacokinetic profile up to 27±1 day ofExample 9 and of Comparative Examples C6 to C9 for the transfer in theporcine femoral arterial tissue.

FIG. 12 is a graph showing percent area stenosis at 28 days of Example10 and of Comparative Examples C6-b to C8-b, C10 and C11 for theintravascular stenosis inhibitory effect in porcine coronary arteries.

FIG. 13 is a graph showing uniformity of area stenosis rate (%) at 28days of Example 10, Comparative Examples C6-b and C11 for theintravascular stenosis inhibitory effect in porcine coronary arteries.

FIG. 14 is scanning electron microscope images of Example 10, showinguniform paclitaxel micro-crystals.

FIG. 15 is scanning electron microscope images of Comparative ExampleC6-b (C6-b), showing a non-uniform drug coating layer.

FIG. 16 is a graph showing the pharmacokinetic profile of Example 9,Comparative Example 6-a (C6-a), Comparative Example 7-a (C7-a) andComparative Example 13 (C13) for the transfer in the porcine femoralarterial tissue.

FIG. 17 is a graph showing the AUC of the drug of Example 9, ComparativeExample 6-a (C6-a), Comparative Example 7-a (C7-a) and ComparativeExample 13 (C13) for the transfer in the porcine femoral arterialtissue.

DETAILED DESCRIPTION

It has been determined that a drug coating layer having low toxicity inthe lesion affected area and a high intravascular stenosis inhibitoryeffect, can be provided with a specific crystal form of awater-insoluble drug when delivering medical device coated with a druginto the body.

The following crystal forms are preferably exemplified.

(1) Layer Including Crystalline Morphological Form of Long Hollow Object

The layer having a morphological form including crystals of a longhollow object is a drug coating layer in which a plurality of elongatedbodies having long axes formed of crystals of the water-insoluble drugare present in a brush shape on the substrate surface. The plurality ofelongated bodies are circumferentially arranged in a brush shape on thesubstrate surface. Each of the elongated bodies is independentlypresent, has a length, and has one end (proximal) of the elongated bodyfixed to the substrate surface. The elongated bodies do not form acomposite structure with adjacent elongated bodies, and are notconnected to each other. The long axis of the crystal is nearly linearin shape. The elongated body forms a predetermined angle with respect tothe substrate plane which the long axis intersects. The predeterminedangle is in the range of 45° to 135°. The predetermined angle ispreferably in the range of 70° to 110°, and more preferably in the rangeof 80° to 100°. It is more preferable that the long axis of theelongated body forms an angle of nearly 90° with respect to thesubstrate plane. At least near the distal, the elongated body is hollow.The cross section of the elongated body is hollow in a surfaceperpendicular to the long axis of the elongated body. The hollow crosssection of the elongated body in a surface perpendicular to the longaxis is a polygon. Examples of the polygon include a tetragon, apentagon, and a hexagon. Accordingly, the elongated body has the distal(or distal surface) and the proximal (or proximal surface), and a sidesurface between the distal (or distal surface) and the proximal (orproximal surface) is formed as a long polyhedron which is constitutedwith a plurality of planes. The crystalline morphological formconstitutes the whole of or at least a part of a plane on the substratesurface. For example, the layer including the crystalline morphologicalform of the long hollow object is a layer having the crystallinemorphological form shown in SEM images of FIGS. 1 to 5.

For example, characteristics of the layer having the morphological formincluding the crystals of a long hollow object are as follows.

1) A plurality of elongated bodies (rod) having independent long axes,and the elongated body is hollow.

2) The elongated body has a rod shape.

3) The elongated bodies have long axes, and in many cases, is apolyhedron, in which the cross section of the elongated body in asurface perpendicular to the long axis is polygonal. Equal to or greaterthan 50% by volume of the elongated body crystal is a long polyhedron.The side surface of the polyhedron is mainly a tetrahedron. In somecases, the long polyhedron has a plurality of surfaces (grooves) whichare formed of a reentrant angle in which a vertex is extended in a longaxis direction. Herein, the reentrant angle means that at least one ofthe interior angles of the polygon of a cross section of the elongatedbody in a plane perpendicular to the long axis is greater than an angleof 180°.

4) In many cases, the elongated body having a long axis is a longpolyhedron. When viewed in a cross section perpendicular to the longaxis, the cross section is polygonal, and is observed as a tetragon, apentagon, or a hexagon.

5) A plurality of elongated bodies having independent long axes stand ina row with an angle in a predetermined range, preferably in the range of45° to 135° with respect to the substrate surface, that is, theplurality of elongated bodies having independent long axes nearlyuniformly stand like a forest on the substrate surface. The region wherethe elongated bodies stand like a forest is nearly uniformly formed inthe circumferential direction and the axial direction on the substratesurface. Each angle with respect to the substrate surface of eachindependent elongated body may be different or the same in thepredetermined range.

6) One end (proximal) of each elongated body having an independent longaxis is fixed to the substrate surface.

7) In some cases, in a portion near the substrate surface,particle-like, short rod-like or short curve-like crystals arelaminated. The elongated body which directly or indirectly has a longaxis on the substrate surface is present. Therefore, there is a casewhere the elongated bodies having long axes on the laminate stand like aforest.

8) A length in the axial direction of the elongated body having a longaxis is preferably 5 μm to 20 μm, more preferably 9 μm to 11 μm, andstill more preferably about 10 μm. A diameter of the elongated bodyhaving a long axis is preferably 0.01 μm to 5 μm, more preferably 0.05μm to 4 μm, and still more preferably 0.1 μm to 3 μm.

9) Other morphological forms (for example, a plate shaped morphologicalform which is amorphous) are not mixed on the surface of the layerincluding the crystalline morphological form of a long hollow object,which is present in an amount equal to or greater than 50% by volume,and more preferably equal to or greater than 70% by volume, and ispresent as the crystalline morphological forms of 1) to 7). Morepreferably, almost all of the long hollow object is the crystallinemorphological form of 7).

10) In the crystalline morphological form of the long hollow object, itis possible that other compounds are present in the drug coating layerincluding the water-insoluble drug constituting crystals. In this case,the compounds are present in a state of being distributed in the spacebetween crystals (elongated body) of a plurality of the water-insolubledrugs which stand like a forest on a balloon substrate surface. In theratio of the materials constituting the drug coating layer, the crystalsof the water-insoluble drugs occupy a much greater volume than othercompounds in this case.

11) In the crystalline morphological form of long hollow object, thewater-insoluble drugs constituting crystals are present on the balloonsubstrate surface. In the drug coating layer of the balloon substratesurface having the water-insoluble drugs constituting crystals, a matrixby the excipient is not formed. Therefore, the water-insoluble drugsconstituting crystals are not attached to the matrix material. Thewater-insoluble drugs constituting crystals are also not embedded in thematrix material.

12) In the crystalline morphological form of long hollow object, thedrug coating layer may include crystal particles of the water-insolubledrugs which are arranged with regularity on the substrate surface, andexcipient particles formed of an excipient which are irregularlyarranged between the crystal particles. In this case, a molecular weightof the excipient is less than a molecular weight of the water-insolubledrugs. Therefore, the ratio that the excipient particles occupy per apredetermined area of the substrate is smaller than the ratio thatcrystal particles occupy and the excipient particles do not form amatrix. Here, the crystal particles of the water-insoluble drugs may beone of the elongated body, and since the excipient particles are presentin a state of being much smaller than the crystal particles of thewater-insoluble drugs, and are dispersed among the crystal particles ofthe water-insoluble drugs, there is a case where the excipient particlesare not observed in the SEM image.

(2) Layer Including Flat Hair-Like Shape Crystalline Morphological Form

The flat hair-like shape crystalline morphological form to be describedbelow occupies at least a part of the drug coating layer (including anamorphous form), equal to or greater than 50% by volume, equal to orgreater than 80% by volume, (equal to or greater than 50% by volume as acrystal form, more and preferably equal to or greater than 70% byvolume), and still more preferably nearly 100% by volume. In a case ofoccupying nearly 100% by volume, it is in a state that a plurality ofcrystalline morphological forms are not mixed, and only a singlecrystalline morphological form is present.

The layer including a flat hair-like shape crystalline morphologicalform is a drug coating layer in which crystals of a flatly elongatedhair-like shape of crystals of the water-insoluble drug are randomlylaminated on the substrate surface, and in which some of the crystalshave a portion curved in shape, and crystals having other morphologicalforms are not mixed in the same crystal plane. In a case where anamorphous layer and a crystal layer are present, “not the same crystalplane” means that the amorphous film is present on the crystal layer.For example, the layer including the flat hair-like shape crystallinemorphological form is a layer having the crystal form of Example 6 shownin FIG. 6A.

For example, characteristics of the layer including the flat hair-likeshape crystalline morphological form are as follows.

1) A hair-like shape crystal having a long axis has a shape flatlyjointed in a plurality of width directions, is not hollow, and has atapered shape.

2) The joint shape of the hair-like shape crystal is randomly laminatedon the substrate surface. The long axis is present in a state reclinedalong the substrate surface.

3) Some of the crystals have a portion curved in shape.

4) A length in the long-axis direction of the hair-like shape crystal ispreferably 10 μm to 100 μm, more preferably about 20 μm, and is longerthan a length of the crystalline morphological form of a long hollowobject in many cases.

(3) Layer Including Morphological Form in which an Amorphous Film isPresent on the Surface of the Flat Hair-Like Shape Crystal

The layer is a drug coating layer in which the surface of the flathair-like shape crystal is covered with an amorphous film. The layerincluding the morphological form in which an amorphous film is presenton the surface of the flat hair-like shape crystal, in which a layer ofan amorphous film is present on the flat hair-like shape crystal, isformed of two layers, one of the crystal and the other the amorphousfilm. For example, the layer including the morphological form in whichan amorphous film is present on the surface of the flat hair-like shapecrystal is a layer having the crystal form of Example 6 shown in FIG.6B.

Specifically, on a certain plane (plane in which crystal/amorphous filmare present), a certain crystal form is at least partly present, or acertain crystal form is present in an amount equal to or greater than50% by volume, or equal to or greater than 80% by volume, (equal to orgreater than 50% by volume as a crystal form, and more preferably equalto or greater than 70% by volume), still more preferably a plurality ofcrystal forms are not mixed, and an amorphous film may be present on theoutside of a certain plane.

The crystal layers of the morphological form of the long hollow object,the morphological form of the flat hair-like shape, and themorphological form in which an amorphous film is present on the surfaceof the flat hair-like shape crystal have low toxicity and a highintravascular stenosis inhibitory effect when delivering medical devicein which the substrate surface is coated with a drug into the body as adrug coating layer. While not limiting, it is considered that the reasonis because solubility and retentivity in tissue after a drug having acertain crystal form is transferred into the tissue is affected. Forexample, in a case of an amorphous form, since solubility is high, evenwhen the drug is transferred into a tissue, it immediately flows intothe blood stream. Therefore, the retentivity in a tissue is low, andthus an excellent stenosis inhibitory effect cannot be obtained. On theother hand, the water-insoluble drug having the described specificcrystal form effectively acts to inhibit the stenosis since when thedrug is transferred into a tissue, one unit of the crystal becomessmall, and therefore, the permeability into a tissue and the solubilitythereof are excellent. In addition, it is considered that since thequantity of the drug remaining in a tissue as a large mass is small, thetoxicity is low.

In particular, the layer including the crystalline morphological form ofa long hollow object is a plurality of nearly uniform elongated bodieshaving long axes, and a morphological form which substantially uniformlystands in a row with regularity on the substrate surface. Therefore, thecrystals transferred into a tissue have a small size (length inlong-axis direction) of about 10 μm. For this reason, the drug uniformlyacts on the lesion affected area, and tissue penetrability is increased.Further, it is considered that since the size of the crystalstransferred is small, an excessive amount of the drug does not remain inthe lesion affected area for an excessive amount of time, and thetoxicity is not expressed, and a high stenosis inhibitory effect can beexhibited.

Water-Insoluble Drug

The water-insoluble drug means a drug that is insoluble or poorlysoluble in water, and specifically, solubility in water is less than 5mg/mL at pH 5 to 8. The solubility may be less than 1 mg/mL, andfurther, may be less than 0.1 mg/mL. The water-insoluble drug includes afat-soluble drug.

Examples of some preferable water-insoluble drugs includeimmunosuppressive drugs such as cyclosporines including cyclosporine,immunoactive drugs such as rapamycin, anticancer drugs such aspaclitaxel, an antiviral drug or an antibacterial drug, anantineoplastic tissue drug, an analgesic drug and an antiinflammatorydrug, an antibiotic drug, an antiepileptic drug, an anxiolytic drug, anantiparalysis drug, an antagonist, a neuron blocking drug, ananticholinergic drug and a cholinergic drug, an antimuscarinic drug anda muscarinic drug, an antiadrenergic drug, an antiarrhythmic drug, anantihypertensive drug, a hormone drug, and a nutritional supplement.

The water-insoluble drug is preferably at least one selected from agroup formed of rapamycin, paclitaxel, docetaxel, and everolimus. In thespecification, rapamycin, paclitaxel, docetaxel, and everolimus includeanalogs and/or derivatives thereof as long as these have similar drugefficacy. For example, the paclitaxel is an analogue of the docetaxel.The rapamycin is an analogue of the everolimus. Among these, thepaclitaxel is more preferable.

The water-insoluble drug may further include an excipient. The excipientis not limited as long as it is pharmaceutically acceptable, andexamples thereof include water-soluble polymers, sugars, contrastagents, citric acid esters, amino acid esters, glycerol esters ofshort-chain monocarboxylic acid, pharmaceutically acceptable salts,surfactants, and the like. The ratio of the excipient and thewater-insoluble drug is not limited, but specifically, the ratioexcipient/water-insoluble drug is in the range from 0.5 to 4.0(mol/mol), and more preferably, in the range from 1.0 to 3.2 (mol/mol).The excipient may be amino acid esters, preferably serine ethyl ester,and water-insoluble drug is paclitaxel.

Method for Preparing Crystalline Layer

A coating solution is prepared by dissolving a water-insoluble drug in asolvent. The coating solution is coated on a dilated balloon such thatthe solvent of the coating solution is slowly volatilized. Thereafter,the balloon is deflated after coating is dried, thereby preparing a drugcoating layer including the crystal layer.

The solvent used is not particularly limited and is exemplified bytetrahydrofuran, ethanol, glycerin (also referred to as glycerol orpropane-1,2,3-triol), acetone, methanol, dichloromethane, hexane, ethylacetate, and water. Among these, a mixed solvent in which some fromamong tetrahydrofuran, ethanol, acetone, and water are mixed ispreferable.

A coating solution is applied to the surface of a medical device (e.g.medical device, for example, balloon catheter, etc.) by using a coatingapparatus. The coating apparatus includes a motor, a platform, and adispensing tube. The motor is connected to a rotation member that isfixed to the proximal end of the medical device. The medical device ismounted on the rotation member and configured to rotate about itslongitudinal axis. The medical device is supported on the platform sothat the medical device is rotatable on the platform. The coatingsolution is coated on the surface of the medical device with thedispensing tube. The dispensing tube has a hollow tubular structure, andhas an opening at the distal end. The lateral part of the distal portionof the dispensing tube is disposed to contact the surface of the medicaldevice, and the coating solution is dispensed from the distal openingonto the surface of the medical device. The medical device is rotatedabout the longitudinal axis in the opposition direction (reversedirection) of dispensing the coating solution. The dispensing tubetranslates along the longitudinal axis of the medical device to applythe coating solution on the medical device. The coating solution appliedon the surface of the medical device is dried to form a coating layer.The rotation of the medical device (balloon catheter) is made at 10-200rpm, preferably 30-180 rpm, more preferably 50-150 rpm. Thetranslational movement is made at 0.01-2 mm/sec, preferably 0.03-1.5mm/sec, more preferably 0.05-1.0 mm/sec. The part of the medical device(balloon catheter) where a coating layer is formed has a round orannular shape in cross-section and its diameter is 1-10 mm, preferably2-7 mm. The dispensing of the coating solution on the surface of themedical device is made at 0.01-1.5 μL/sec, preferably 0.01-1.0 μL/sec,more preferably 0.03-0.8 μL/sec.

Medical Device

The medical device can have the drug coating layer applied directly orthrough a pretreatment layer, such as a primer layer, on the surface ofthe substrate. The drug coating layer contains a drug at a density of0.1 μg/mm² to 10 μg/mm², preferably at a density of 0.5 μg/mm² to 5μg/mm², more preferably at a density of 0.5 μg/mm² to 3.5 μg/mm², evenmore preferably at a density of 1.0 μg/mm² to 3.0 μg/mm², but it is notparticularly limited thereto.

The shape and materials of the substrate are not particularly limited.Metals and resins may be used as materials. The material may be any oneof a film, a plate, a wire rod, and an irregularly shaped material, andmay be a particulate.

The medical device used is not limited. Any medical device that istransplantable or insertable may be used. The medical device which islong, delivered in the non-dilated state with a reduced diameter in abody cavity such as blood, and enlarged in diameter in a circumferentialdirection at a part, such as a blood vessel or a tissue, to release adrug from the drug coating layer is preferable. Therefore, the medicaldevice that is reduced in diameter to be delivered, and enlarged indiameter to be applied to an affected area is a medical device having adilation portion. The drug coating layer is provided on at least a partof the surface of the dilation portion. That is, the drug is coated on,at least, the outer surface of the dilation portion.

The materials of the dilation portion of the medical device preferablyhave a certain degree of flexibility, and a certain degree of hardnesssuch that the drug is released from the drug coating layer on thesurface by being dilated when the medical device reaches a blood vesselor a tissue. Specifically, the medical device is constituted with ametal or a resin, and the surface of the dilation portion on which thedrug coating layer is provided is preferably constituted of a resin. Theresin constituting the surface of the dilation portion is notparticularly limited, and preferable examples thereof includepolyamides. That is, at least a part of the surface of the dilationportion of the medical device which is coated with a drug is apolyamide. Examples of the polyamide, which is not particularly limitedas long as it is a polymer having an amide bond, include homopolymerssuch as polytetramethylene adipamide (Nylon 46), polycaprolactam (Nylon6), polyhexamethylene adipamide (Nylon 66), polyhexamethylene sebacamide(Nylon 610), polyhexamethylene dodecamide (Nylon 612),polyundecanolactam (Nylon 11), polydodecanolactam (Nylon 12), coploymerssuch as a caprolactam/lauryl lactam copolymer (Nylon 6/12), acaprolactam/aminoundecanoic acid copolymer (Nylon 6/11), acaprolactam/co-aminononanoic acid copolymer (Nylon 6/9), acaprolactam/hexamethylene diammonium adipate copolymer (Nylon 6/66), andaromatic polyamides such as a copolymer of adipic acid and m-xylenediamine, or a copolymer of hexamethylene diamine and m,p-phthalic acid.Further, a polyamide elastomer which is a block copolymer in which Nylon6, Nylon 66, Nylon 11, or Nylon 12 is a hard segment, and a polyalkyleneglycol, a polyether, or an aliphatic polyester is a soft segment can beused as a substrate material for a medical device. The polyamides may besolely used, or two or more kinds thereof may be jointly used.

Specifically, as the medical device having the dilation portion, a longcatheter having a dilation portion (stent) or a dilation portion(balloon) is exemplified (balloon catheter).

In the balloon of one embodiment, preferably, the drug coating layer isformed on the surface at the time of dilating, and the balloon iswrapped (folded), inserted into a blood vessel, a body cavity or thelike, delivered to tissue or affected area, and enlarged in diameter inthe affected area, and then, the drug is released.

Method of Treating Peripheral Artery Diseases in Lower Limbs

As mentioned above, a medical device is provided as DEB having anexpandable member (e.g., a balloon) having a drug coating layer whichhas a crystalline morphological form including a plurality of crystalparticles of water-insoluble drug regularly arranged and uniformly sizedon the surface of the medical device. The medical device is inserted inperipheral blood vessels, through an incision of an access point made inan artery. An access point can be made in radial artery or femoralartery, which is called a trans-radial approach or a trans-femoralapproach, respectively. The medical device is introduced in the arterythrough the access point using other medical devices like guidewires andguiding catheters to the lesion of peripheral artery diseases to betreated in the lower limbs. When the medical device is positioned nextto the lesion, an expandable member is dilated by fluid and expanded.The drug coating layer of the surface of the expandable member contactsand is pressed to the wall of the blood vessels. The drug is immediatelyreleased from the surface of the expandable member, and at least part ofa plurality of crystal particles are transferred to the vascular tissueof the blood vessels. The expandable member is deflated and the medicaldevice is withdrawn from the blood vessels.

By using the medical device as described herein, methods are providedtreating peripheral artery diseases in lower limbs. The lesions ofperipheral artery diseases are formed by arterial sclerosis which isgenerated by/with aging, infection, diabetes mellitus, and the like inthe blood vessels (arteries) of lower limbs. As described herein, it wasshown that the size of the microparticulates generated in the lesion issmall enough and generation of the relatively large microparticulateshaving a size that can cause embolization of peripheral blood vessels issuppressed. This is thought to be caused by crystal particles ofpaclitaxel uniformly arranged and constantly sized in the drug coatinglayer on the surface of the balloon. It was demonstrated that DEB asdescribed herein is capable of reducing the risk of peripheralembolization because of less distribution of microparticulates in themuscle adjacent downstream peripheral blood vessels compared to DEBmanufactured by others. This was shown in the experiments to see theeffects of microparticulates on muscles adjacent downstream peripheralblood vessels using porcine lower limbs.

As described herein, a pharmacokinetic profile (PK profile) is providedby using DEB. This PK profile is achieved by uniform paclitaxel crystalparticles in a micro size. A high drug concentration in tissue by day 7after dilation of the balloon affects smooth muscle cell proliferation.After that, prompt clearance from the tissue does not inhibitendothelial cell growth. The DEB provides superior outcomes in bothefficacy and safety. That is, the DEB disclosed herein can give noinfluence on the vascular remodeling, which reduces the risk of its latethrombosis. Although it strongly inhibits the stenosis, dualanti-platelet therapy (DAPT) expects to be limited for 4 weeks to thesame extent that non-drug coated balloon provides. The PK profilecomprises the area under the blood concentration-time curve (AUC) of thedrug on day 0.04 (60 minutes) to day 7 after the balloon dilation is atleast 200 ng day/mg tissue, the drug concentration in the tissue is 5ng/mg tissue to 40 ng/mg, and more preferably 9 ng/mg tissue to 40 ng/mgtissue on day 7, the drug concentration in the tissue is 0.5 ng/mgtissue to 3 ng/mg tissue on day 28, and the reduction rate of the drugfrom 0.04 day to 1 day was at most 50%.

As described herein, it was shown that DEB provides uniform inhibitoryeffects of vascular intima thickening in the entire treated lesion (inthe entire long lesion). The long lesion is treated by, for example, aballoon catheter having a longitudinal length in the range of 4 cm to 20cm. This is achieved by the micro crystals of paclitaxel uniformlyarranged and constantly sized in the drug coating layer on the surfaceof the balloon. Further, the micro crystals of paclitaxel are deliveredwithout being detached from the surface of the balloon during a processto be delivered to the lesion of the treatment. DEB can be expanded inthe lesion of the treatment while keeping the uniformity (regulararrangement and uniform sizing of a plurality of crystal particles) ofthe drug coating layer until dilated. This is how DEB can uniformlydeliver drugs, such as paclitaxel to the entire lesion. The size ofuniformly arranged paclitaxel crystals is not limited in particular. Thecrystal size can be, for example, both in the range from 0.5 μm to 5 μm,and in the range 5 μm to 30 μm.

EXAMPLES

Hereinafter, examples and the comparative examples will be described,but, the embodiments are not limited to the examples.

A. Manufacture or Preparation of Drug Eluting Balloon, or Preparation ofNon-Drug Coated Balloon Example 1

(1) Preparation of Coating Solution 1

L-serine ethyl ester hydrochloride (CAS No. 26348-61-8) (56 mg) andpaclitaxel (CAS No. 33069-62-4) (134.4 mg) were weighed. Absoluteethanol (1.2 mL), tetrahydrofuran (1.6 mL), and RO (reverse osmosis)membrane-treated water (hereinafter, referred to as RO water) (0.4 mL)were respectively added thereto and dissolved, thereby preparing acoating solution 1.

(2) Drug Coating on Balloon

A balloon catheter (manufactured by Terumo Corp., the material of theballoon (dilation portion) is a nylon elastomer) having a size of adiameter 3.0×a length 20 mm (dilation portion) when dilated wasprepared. The coating solution 1 was coated on the dilated balloon suchthat the solvent of the coating solution is slowly volatilized to makethe amount of paclitaxel be about 3 μg/mm². That is, a dispensing tubehaving an opening at the distal most end was transferred horizontally inthe traverse direction and was placed on the surface of the balloon. Atleast a portion of the lateral side of the dispensing tube was contactedand disposed along the surface of the balloon. While at least a portionof the lateral side of the dispensing tube was maintained in contactwith the surface of the balloon, the coating solution was dispensed fromthe opening at the distal most end of the dispensing tube. In this statethe balloon was rotated about the longitudinal axis in the oppositedirection (reverse direction) against the direction of the dispensingthe coating solution from the distal opening. The translational movementof the dispensing tube along the longitudinal axis and the rotationalmovement of the balloon were adjusted, and concurrent with the beginningof the rotation, the coating solution was dispensed on the surface ofthe balloon at 0.053 μL/sec to perform coating of the balloon.

Thereafter, the coating was dried, thereby making a drug elutingballoon.

Example 2

(1) Preparation of Coating Solution 2

L-serine ethyl ester hydrochloride (70 mg) and paclitaxel (180 mg) wereweighed. Absolute ethanol (1.5 mL), acetone (2.0 mL), tetrahydrofuran(0.5 mL), and RO water (1 mL) were added thereto respectively anddissolved, thereby preparing a coating solution 2.

(2) Drug Coating on Balloon

A balloon catheter (manufactured by Terumo Corp., the material of theballoon (dilation portion) is a nylon elastomer) having a size of adiameter 3.0×a length 20 mm (dilation portion) when dilated wasprepared. The coating solution 2 was coated on the dilated balloon suchthat the solvent of the coating solution is slowly volatilized to makethe amount of paclitaxel be about 3 μg/mm².

That is, the coating was performed as in the Example 1 except that thecoating solution was dispensed on the surface of the balloon at 0.088μL/sec.

Thereafter, the coating was dried, thereby making a drug elutingballoon.

Example 3

(1) Preparation of Coating Solution 3

L-serine ethyl ester hydrochloride (70 mg) and paclitaxel (168 mg) wereweighed. Absolute ethanol (1.5 mL), tetrahydrofuran (1.5 mL), and ROwater (1 mL) were added thereto respectively and dissolved, therebypreparing a coating solution 3.

(2) Drug Coating on Balloon

A balloon catheter (manufactured by Terumo Corp., the material of theballoon (dilation portion) is a nylon elastomer) having a size of adiameter 3.0×a length 20 mm (dilation portion) when dilated wasprepared. The coating solution 3 was coated on the dilated balloon suchthat the solvent of the coating solution is slowly volatilized to makethe amount of paclitaxel be about 3 μg/mm².

That is, the coating was performed as in the Example 1 except that thecoating solution was dispensed on the surface of the balloon at 0.101μL/sec.

Thereafter, the coating was dried, thereby making a drug elutingballoon.

Example 4

(1) Preparation of Coating Solution 4

L-serine ethyl ester hydrochloride (70 mg) and paclitaxel (180 mg) wereweighed. Absolute ethanol (1.75 mL), tetrahydrofuran (1.5 mL), and ROwater (0.75 mL) were added thereto respectively and dissolved, therebypreparing a coating solution 4.

(2) Drug Coating on Balloon

A balloon catheter (manufactured by Terumo Corp., the material of theballoon (dilation portion) is a nylon elastomer) having a size of adiameter 3.0×a length 20 mm (dilation portion) when dilated wasprepared. The coating solution 4 was coated on the dilated balloon suchthat the solvent of the coating solution is slowly volatilized to makethe amount of paclitaxel be about 3 μg/mm².

That is, the coating was performed as in the Example 1 except that thecoating solution was dispensed on the surface of the balloon at 0.092μL/sec.

Thereafter, the coating was dried, thereby making a drug elutingballoon.

Example 5

(1) Preparation of Coating Solution 5

L-aspartic acid dimethyl ester hydrochloride (CAS No. 32213-95-9) (37.8mg) and paclitaxel (81 mg) were weighed. Absolute ethanol (0.75 mL),tetrahydrofuran (0.96 mL), and RO water (0.27 mL) were added theretorespectively and dissolved, thereby preparing a coating solution 5.

(2) Drug Coating on Balloon

A balloon catheter (manufactured by Terumo Corp., the material of theballoon (dilation portion) is a nylon elastomer) having a size of adiameter 3.0×a length 20 mm (dilation portion) when dilated wasprepared. The coating solution 5 was coated on the dilated balloon suchthat the solvent of the coating solution is slowly volatilized to makethe amount of paclitaxel be about 3 μg/mm².

That is, the coating was performed as in the Example 1 except that thecoating solution was dispensed on the surface of the balloon at 0.055μL/sec.

Thereafter, the coating was dried, thereby making a drug elutingballoon.

Example 6

(1) Preparation of Coating Solution 6

L-serine ethyl ester hydrochloride (56 mg) and paclitaxel (134.4 mg)were weighed. Absolute ethanol (0.4 mL), tetrahydrofuran (2.4 mL), andRO water (0.4 mL) were added thereto respectively and dissolved, therebypreparing a coating solution 6.

(2) Drug Coating on Balloon

A balloon catheter (manufactured by Terumo Corp., the material of theballoon (dilation portion) is a nylon elastomer) having a size of adiameter 3.0×a length 20 mm (dilation portion) when dilated wasprepared. The coating solution 6 was coated on the dilated balloon suchthat the solvent of the coating solution is slowly volatilized to makethe amount of paclitaxel be about 3 μg/mm².

That is, the coating was performed as in the Example 1 except that thecoating solution was dispensed on the surface of the balloon at 0.053μL/sec.

Thereafter, the coating was dried, thereby making a drug elutingballoon.

Comparative Example 1

IN.PACT® (manufactured by INVAtec JAPAN, Interventional Cardiology,58(11), 2011, 1105-1109) which is a commercially available drug-elutingballoon catheter comprising paclitaxel and an excipient of urea wasprovided. The balloon in Comparative Example 1 is a drug eluting balloonof which the surface is coated with paclitaxel.

Comparative Example 2

A balloon catheter (manufactured by Terumo Corp., the material of theballoon (dilation portion) is a nylon elastomer) having a size of adiameter 3.0×a length 20 mm (dilation portion) when dilated wasprepared. The balloon in Comparative example 2 is a non-drug coatedballoon of which the surface is not coated with a drug.

B. Measurement of Amount of Paclitaxel Coated on Balloon

For the drug eluting balloon in Examples 1 to 6, the amount ofpaclitaxel coated on the balloon was measured according to the followingprocedure.

1. Method

After the prepared drug eluting balloon was immersed in a methanolsolution, it was shaken with a shaking apparatus for 10 minutes, andthen, paclitaxel coated on the balloon was extracted. The absorbance at227 nm of the methanol solution by which paclitaxel was extracted wasmeasured by high performance liquid chromatography using anultraviolet-visible spectrophotometer, and the amount of paclitaxel perballoon ([μg/balloon]) was determined. In addition, the amount ofpaclitaxel per unit area of balloon ([μg/mm²]) was calculated from theamount of obtained paclitaxel and the balloon surface area.

2. Result

Table 1 shows the obtained results. In addition, in Table 1, “Balloonsurface area” represents a surface area (unit: mm²) when the balloon isdilated, “per each balloon” in “Amount of PTX on a balloon” representsthe amount of paclitaxel per one balloon (unit: μg/balloon), and “perunit area” in “Amount of PTX on a balloon” represents the amount ofpaclitaxel per surface area 1 mm² of the balloon (unit: μg/mm²),respectively.

As shown in Table 1, the amount of paclitaxel coated on the balloon inall of Examples 1 to 6 is about 3 μg/mm², and it was possible to coatthe target amount of paclitaxel on the balloon surface.

TABLE 1 Coating Amount of PTX on a balloon solution per each per unitarea Examples No. [μg/balloon] [μg/mm²] 1 Coating solution 1 588.9 3.1 2Coating solution 2 665.5 3.5 3 Coating solution 3 652.6 3.5 4 Coatingsolution 4 661.3 3.5 5 Coating solution 5 653.3 3.5 6 Coating solution 6560.2 3.0

C. Observation of Drug Coating Layer of Drug Eluting Balloon by ScanningElectron Microscope (SEM)

1. Method

The drug eluting balloons in Examples 1 to 5 and Example 6 were dried,and after the dried drug eluting balloons were cut to an appropriatesize, these were placed on a support, and platinum deposition wasperformed thereon. In addition, in the same manner, after a commerciallyavailable drug eluting balloon (IN.PACT) manufactured by INVAtec JAPANin Comparative Example 1 also was cut to an appropriate size, it wasplaced on a support, and platinum deposition was performed thereon. Thesurface and the inside of the drug coating layers of these platinumdeposited samples were observed by a scanning electron microscope (SEM).

2. Result

In the drug coating layers of the Examples, crystal layers having amorphological form of a long hollow object, a morphological form of aflat hair-like shape, and a morphological form in which an amorphousfilm is present on the surface of the flat hair-like shape crystals wereobserved.

SEM images shown in FIGS. 1 to 6 were obtained. FIGS. 1 to 5, which areSEM images of Examples 1 to 5, show a layer, including the morphologicalform of a long hollow object, and it was made clear that uniformpaclitaxel crystals of the long hollow objects having a length of about10 μm are uniformly formed on the balloon surface. These paclitaxelcrystals of the long hollow objects have long axes, and the elongatedbodies (about 10 μm) having the long axes were formed so as to be in adirection nearly perpendicular to the balloon surface. The diameter ofan elongated body was about 2 μm. In addition, the cross section of theelongated body in a surface perpendicular to the long axis was apolygon. The polygon was, for example, a polygon of a tetragon. Further,these nearly uniform long hollow objects of paclitaxel were uniformlyand densely (at the same density) formed on the entire surface of theballoon in the same morphological form (structure and shape).

On the other hand, SEM images of FIG. 6A and FIG. 6B in Example 6 show alayer including a morphological form of a flat hair-like shape and amorphological form in which an amorphous film is present on the surfaceof the flat hair-like shape crystals, which were paclitaxel crystals ofa flatly elongated hair-like shape. Many of these crystals have acomparatively large size equal to or greater than 20 μm, and the longaxes are present in a state reclined along the balloon surface (FIG.6A). Further, as shown in FIG. 6B, a region in which the upper portionof a layer including a morphological form of a flat hair-like shape iscovered with an amorphous film was present. In the region, the layerincluding a morphological form in which a layer of an amorphous film ispresent on the flat crystal structure, two layers are formed of thecrystals and the amorphous film, and the amorphous film is present onthe surface of the flat hair-like shape crystals.

FIG. 7 in Comparative example 1 is a SEM image of the drug coating layerof a commercially available drug eluting balloon (IN.PACT) manufacturedby INVAtec JAPAN. In this, amorphous material and crystals were mixed inthe same plane. It was observed that most of them were nearly amorphous,and needle-like crystals were partly mixed in the same plane.

D. Intravascular Stenosis Inhibitory Effect in a Pig Coronary Artery andEffect on Blood Vessel Remodeling

For Examples 1 and 6, Comparative Example 1 (C1: commercially availableballoon), and Comparative Example 2 (C2: non-drug coated balloon), theintravascular stenosis inhibitory effect in a pig coronary artery and aneffect on blood vessel remodeling were evaluated in according to thefollowing procedure.

1. Method

(1) A guiding catheter with a guide wire was inserted by an 8 Fr sheath,and guided to the left and right coronary artery opening portion underX-ray fluoroscopy.

(2) Angiography of each coronary artery was performed (coronary artery:left anterior descending coronary artery (LAD), right coronary artery(RCA), and left circumflex coronary artery (LCX)), and a diameter ofcoronary artery obtained by angiography was measured by a QCA software.

(3) A site in which a diameter of a stent is 1.2 times, and a diameterof the drug eluting balloon is 1.3 times with respect to a diameter of ablood vessel was selected, and work after stent placement was performed.

(4) After extended for 30 seconds such that BMS (bare metal stent) stent(stent diameter 3 mm×length 15 mm) in the coronary artery selected is1.2 times, a balloon catheter for the stent placement was removed. Atthe stent placement site, after the drug eluting balloon (balloondiameter 3 mm×length 20 mm) having the drug coating layer prepared inExamples 1 and 6 and Comparative Examples 1 and 2 was dilated for 1minute so as to be 1.3 times with respect to the diameter of a bloodvessel, the balloon catheter was removed.

(5) After the drug eluting balloon was dilated, the guiding catheter andthe sheath were removed. After a central side of a carotid artery wasligated, a gap of muscles of an incision opening of cervical region wassutured with a suture, and the skin was sutured by a surgical staplerfor sutures.

(6) 28 days after the balloon dilatation, autopsy was performed.

Calculation Method of Intravascular Stenosis Rate

An intravascular stenosis rate was calculated in according to thefollowing procedure.

Blood vessel images were taken by a Leica microscope and a pathologyimaging system. By these images, internal area of an external elasticlamina area, internal elastic lamina area, internal area of lumen,internal area of stent were measured.

Area stenosis rate (%) was calculated from “area stenosisrate=(neointimal area/internal elastic lamina area)×100”.

Calculation Method of Fibrin Content, Fibrin Content Score

Evaluation of fibrin content was performed in all circumferences ofblood vessel according to the method of Suzuki et al. (Suzuki Y., et. alStent-based delivery of sirolimus reduces neointimal formation inaprocine coronary model. Circulation 2001; 1188-93).

The content of the score of fibrin content is as follows.

Score 1: Fibrin localized in a blood vessel was observed, or fibrin ismoderately deposited in a region less than 25% of all circumferences ofblood vessel observable near a strut of the stent.

Score 2: Fibrin is moderately deposited in a region greater than 25% ofall circumferences of blood vessel observable, or fibrin is heavilydeposited in a region less than 25% of all circumferences of bloodvessel observable between the struts and the proximity of the strut.

Score 3: Fibrin is severely deposited in a region greater than 25% ofall circumferences of blood vessel observable.

In addition, all the scores were obtained by calculating the averagevalue of the three locations, that is, a proximal location, a middlelocation, and a distal location of the stent placement sites for eachblood vessel.

Endothelialization Score Calculation Method, Endothelialization Score

The content of an endothelialization score is as follows.

Score 1: Up to 25% of all circumferences of vascular lumen observable iscovered with endothelial cells.

Score 2: 25% to 75% of all circumferences of vascular lumen observableis covered with endothelial cells.

Score 3: Equal to or greater than 75% of all circumferences of vascularlumen observable is covered with endothelial cells.

In addition, all the scores were calculated as an average value of threelocations, that is, a proximal, a middle and a distal location to thestent placement site, for each blood vessel.

2. Results for Intravascular Stenosis Inhibitory Effect in a PigCoronary Artery

An intravascular stenosis rate was calculated according to theabove-described procedure. Table 2 shows the obtained results. In Table2, 1 and 6 in a column of Examples/Comparative Examples are Examples,and C1 to C2 are Comparative Examples.

In addition, FIG. 8 is a graph showing the blood vessel stenosis rate ofExamples 1 and 6, and of Comparative Examples C1 to C2 for theintravascular stenosis inhibitory effect in pig coronary arteries. InFIG. 8, the horizontal axis represents Examples or Comparative Examples,the numbers 1 and 6 mean Examples 1 and 6, respectively, and the numberswith letters, that is, C1 to C2 mean Comparative Example 1 (C1) andComparative Example 2 (C2), respectively. In addition, the vertical axisrepresents the area stenosis rate (unit: %) of a blood vessel.

In Comparative Example 2 (C2), the area stenosis rate of a blood vesseltreated with the non-drug coated balloon as a non-drug treated controlwas 38.9%. The area stenosis rate of a blood vessel treated with thedrug eluting balloon in Example 6 was 20.6%, and a significant stenosisinhibitory effect was confirmed as compared to the non-drug treatedcontrol. On the other hand, the area stenosis rate of a blood vesseltreated with the commercially available drug eluting balloon (IN.PACT)in Comparative Example 1 was 30.4%, and it was found that the areastenosis rate tends to be decreased as compared to the non-drug coatedballoon; however, it was estimated that there is sufficient room forimprovement in the effect.

In contrast, the area stenosis rate of a blood vessel treated with thedrug eluting balloon according to Example 1 was 16.8%, and a significantstenosis inhibitory effect was observed as compared to the non-drugtreated control and the IN.PACT of Comparative Example 1 (C1). Inaddition, it showed a stronger effect than in Example 6, and the mostexcellent stenosis inhibitory effect was obtained.

Based on what has been described above, it was made clear that the drugeluting balloon of the drug coating layer having the paclitaxelcrystalline morphological form according to Examples 1 and 6 exhibits asignificantly stronger stenosis inhibitory effect than the commerciallyavailable drug eluting balloon.

TABLE 2 Examples/ Stenosis Comparative rate Examples [%] S.D. 1 16.8 3.96 20.6 5.9 C1 30.4 10.3 C2 38.9 13.83. Results for Blood Vessel Remodeling after Stent Placement in a PigCoronary Artery (Toxicity)

As the effect (toxicity) on the blood vessel remodeling after the stentplacement in a pig coronary artery, the fibrin content score andendothelialization score were observed. The results are shown in Table3. Moreover, the larger the number the fibrin content score is, thelarger the fibrin content is, which is not preferable. On the otherhand, the smaller the number the endothelialization score is, the lessblood vessel is covered with the endothelial cells, which is notpreferable. In Table 3, 1 and 6 in a column of Examples/ComparativeExamples are Examples, and C1 and C2 are Comparative Examples.

The fibrin content score and endothelialization score of a blood vesseltreated with the non-drug coated balloon as a non-drug treated controlin Comparative Example 2 (C2) do not have an influence on the vascularremodeling since there is no effect (toxicity) by drugs, and the scoreswere 1.00±0.00 and 3.00±0.00, respectively.

The fibrin content score and endothelialization score in ComparativeExample 1 (C1) were 1.27±0.15 and 2.80±0.11, respectively, and thescores were nearly the same as those in the non-drug coated balloon. Itis estimated that effect (toxicity) on the vascular remodeling is alsosmall since the stenosis inhibition effect by drugs is small.

On the other hand, the fibrin content score and endothelialization scoreof a blood vessel treated with the drug eluting balloon according toExample 6 were 2.61±0.16 and 1.78±0.17, respectively, and it wassuggested that the effect on the vascular remodeling was great ascompared to those of Comparative Example 1 (C1) and Comparative Example2 (C2). It is considered that this is because the stenosis inhibitioneffect is stronger than in Comparative Example 1 (C1) and ComparativeExample 2 (C2).

In contrast, the fibrin content score and endothelialization score of ablood vessel treated with the drug eluting balloon according to Example1 were 1.53±0.17 and 2.87±0.09, respectively, and it was made clear thatthe effect (toxicity) on the vascular remodeling was the same as that ofthe commercially available product in Comparative Example 1 (C1), and inspite that high stenosis inhibition effect was obtained, the toxicitywas extremely low.

Based on what has been described above, the drug eluting balloon of thedrug coating layer having the paclitaxel crystalline morphological formaccording to Example 6 has a significantly stronger stenosis inhibitioneffect. Further, it was made clear that the drug eluting balloon of thedrug coating layer having the paclitaxel crystalline morphological formaccording to Example 1 has a significantly stronger stenosis inhibitioneffect, hardly exhibits the effect (toxicity) on the vascularremodeling, and thus, it is an excellent drug eluting balloon in termsof effectiveness and side effects (toxicity).

TABLE 3 Examples/ Comparative Fibrin content Endothelialization Examplesscore score 1 1.53 ± 0.17 2.87 ± 0.09 6 2.61 ± 0.16 1.78 ± 0.17 C1 1.27± 0.15 2.80 ± 0.11 C2 1.00 ± 0.00 3.00 ± 0.00

E. Particulate Sizes Generated from the Drug Eluting Balloon

For the drug eluting balloon in Example 7 and Comparative Example 3(C3), particulate suspensions were generated by tracking drug elutingballoon through a simulated peripheral model and collected.

Example 7

Preparation of Drug Eluting Balloon

A balloon catheter (manufactured by Terumo Corp., the material of theballoon (dilation portion) is a nylon elastomer) having a size of adiameter 7.0×a length 200 mm (dilation portion) when dilated wasprepared.

Coating solution 2 was prepared. The coating solution 2 was coated onthe dilated balloon such that the solvent of the coating solution isslowly volatilized to make the amount of paclitaxel be about 3 μg/mm².

That is, the coating was performed as in the Example 2.

Comparative Example 3

IN.PACT® (manufactured by INVAtec/Medtronic, Inc., same as mentioned inComparative Example 1 above) which is a commercially available ballooncatheter having a size of a diameter 7.0×a length 120 mm (dilationportion) when dilated was provided. The balloon in Comparative Example 3is a drug eluting balloon of which the surface is coated withpaclitaxel.

1. Method

Particulate suspensions were generated according to the followingprocedure. A guiding sheath was filled with normal saline and was sethaving an angle of about 45 degrees. And then, a guide wire was passedthrough a lumen of the guiding sheath. During this test, normal salinein the guiding sheath was kept at 37° C. The drug eluting balloon wastracked over a guide wire for 1 minute until the balloon exited themodel (the guiding sheath) into a mock vessel made of silicone rubbertubing in which the guiding sheath is placed. The balloon was inflatedto 11 atm, held for 1 minute, deflated, and retracted through the model.A guiding sheath was flushed with physiological salt solution. The mockvessel was flushed with normal saline. All flush solutions were pooledin glass vials. Measurement of particulate counts and sizes wereperformed by a Liquid Particle Counter HIAC 8000A (Hach Company) and amicroscope VH-5500 (KEYENCE).

2. Result

Particulates generated by the drug eluting balloon tracked through asimulated peripheral model with balloon expansion in a silicone rubbermock vessel (mean total counts per balloon catheter) was measured. Theresults are shown in FIG. 9A and FIG. 9B. In FIG. 9A and FIG. 9B, 7 isExample, and C3 is Comparative Example 3.

It was shown that the drug eluting balloon in Example 7 generated anapproximate 10-fold higher number of particulates having a diameter of10-25 μm (fine particulates) per balloon catheter than the drug elutingballoon (IN.PACT®) in Comparative Example C3. In addition, the drugeluting balloon in Example 7 also generated fewer large-sizedparticulates 100-900 μm than IN.PACT in Comparative Example C3. In thisembodiment, greater than 90% of the total particulates generated fromthe drug eluting balloon in Example 7 was 10-25 μm in diameter, and therest (10% or less) of the particulates is 100-900 μm in diameter asshown in FIG. 9A and FIG. 9B.

F. Histologic Evaluation Downstream Vascular and Skeletal Muscle

For the drug eluting balloon in Example 7 and Comparative Example 4(C4), histologic evaluation of downstream vascular and skeletal muscle(in the peripheral arteries of the lower limb) was performed inaccording to the following procedure.

Comparative Example 4 (C4)

Comparative Example 4 (C4) in Table 4 is data of the commerciallyavailable drug coating balloon (Lutonix®) manufactured by Bard, that isreferred to the literature (Catheterization and CardiovascularInterventions 83, 2014, 132-140), which comprises paclitaxel and acarrier comprised of polysorbate and sorbitol.

1. Method

Particulate suspensions were generated by using a simulated peripheralmodel as in Example 7. Five porcine were designated to histologicevaluation of downstream vascular and skeletal muscle. After the drugeluting balloon treatment procedure has concluded, the animals wererecovered and allowed to reach the predetermined 29±1 day survival timepoint. A single animal received intra-arterial injection of either 1×clinical dose (3 μg/mm² paclitaxel) or 3× dose (correspond to 9 μg/mm²paclitaxel) particulate suspension or control suspension to the left andright iliofemoral arteries. For each injection, the guiding catheter waspositioned in a distal end of bifurcation of superficial femoralarteries and deep femoral arteries and paclitaxel particle suspension orcontrol suspension was injected over a period of approximately 5 sec.Immediately following injection, the catheter was flashed withapproximately 20 ml of normal saline to ensure the entire suspension hadbeen delivered to the target area. An angiogram was performed to assessvessel patency. The presence of emboli within lower limb muscles wasevaluated at 29±1 day by sectioning the semitendinosus, semimembranous,biceps femoris, Gastroconnemius femoris, musculus soleus, flexordigitorum profundus and flexor digitorum superficialis with parallelcuts at 1-2 cm apart. Histologic sections were prepared on a microtomeat 3-4 microns and stained with hematoxylin and eosin (H&E). Thehistologic sections immunostained with anti-von Willebrand factorantibodies (Abcam) to detect endothelial cells. Histologic sections wereexamined to identify and quantify any embolic particulate as well as anyassociated regions of ischemic necrosis/inflammation. The number ofarterioles with findings was expressed as a percentage of total numberof arterioles histologic section.

Histological analyses of downstream skeletal muscle were performed todetermine whether there is any evidence of ischemia from downstreamemboli.

2. Result

Percentage of arterioles with any pathological findings downstream suchas emboli and necrosis were evaluated. Table 4 shows the obtainedresults. In Table 4, “7” in column of Examples/Comparative Examples isan Example, and “C4” is a Comparative Example.

In Example 7, the percentage of arterioles with any pathologicalfindings downstream of 3× dose treated arteries was maximally 0.012% at28 days. It was showed that changes in skeletal muscle sections wereoverall very low. In addition, the percentage of downstream emboliand/or necrosis observed in Example 7 was less than Lutonix® accordingto Comparative Example 4 (C4) (Catheterization and CardiovascularInterventions, 83, 2014, 132-140). Example 7 showed favorable downstreamsafety. It was shown that the drug eluting balloon as described hereinhas an effect with the decreased level of necrosis in the peripheralarteries.

TABLE 4 Examples/ Thromboemboli/Vasculitis Comparative PTX dose(arterioles with findings/total) Examples [μg] [%] 7 15825.6 (×1 dose)0.002 7 47476.8 (×3 dose) 0.012 C4 3014.4 0.18 C4 12057.6 0.24

G. Drug Concentration in Downstream Muscle

For the drug eluting balloon in Example 8 and Comparative Example 5(C5), a concentration of paclitaxel distributed in downstream muscle wasevaluated in according to the following procedure.

Example 8

Preparation of Drug Eluting Balloon

A balloon catheter (manufactured by Terumo Corp., the material of theballoon (dilation portion) is a nylon elastomer) having a size of adiameter 6.0×a length 40 mm (dilation portion) when dilated wasprepared.

Coating solution 2 was prepared. The coating solution 2 was coated onthe dilated balloon such that the solvent of the coating solution isslowly volatilized to make the amount of paclitaxel be about 3 μg/mm².

That is, the coating was performed as in the Example 2.

Comparative Example 5 (C5)

“C5” in Table 5 is from the data of IN.PACT® normalized to the dose ofExample 8. The IN.PACT® data was presented by R. J. Melder, Sc. D. atLINC 2013 (IN.PACT DEB technology and Pre-clinical Science).

1. Method

Three porcine animals were designated to evaluate the amount ofpaclitaxel distributed in downstream muscle (in the peripheral arteriesof the lower limb). At the treatment procedure, angiography was utilizedto identify target treatment sites within the iliofemoral andsuperficial femoral arteries. One drug eluting balloon treatment wasperformed per animal. After the drug eluting balloon treatment procedurehas concluded, the animals were recovered and allowed to reach thepredetermined 1 day (24±0.5 hours) survival time point. Muscles (beneathdilated segment [treatment site] and downstream) was carefully dissectedfrom surrounding tissue at 1 day (24±0.5 hours) following treatment withthe drug eluting balloon. The paclitaxel concentration measurement inmuscle was performed by LC-MS/MS analysis.

2. Result

The amount of paclitaxel distributed in downstream muscle correlateswith sequence of drug exposure was evaluated. Table 5 shows thepaclitaxel concentration in downstream muscle. In Table 5, “8” in columnof Examples/Comparative Examples is an Example, and “C5” is aComparative Example.

The paclitaxel concentration in downstream muscle observed in Example 8is less than IN.PACT of Comparative Example 5 (C5).

Based on what has been described above, it was made clear that the drugeluting balloon disclosed herein is capable of reducing the risk ofperipheral embolization because of less distribution of (large-sized)micro-particulates in downstream muscle compared to drug eluting balloonmanufactured by others.

TABLE 5 Examples/ PTX concentration Comparative in downstream MuscleExample [ng/mg] 8 0.0176 C5 0.0529

H. Pharmacokinetics in Porcine Ilio-Femoral Arteries

For the drug eluting balloon in Example 9 and Comparative Example 6-a(C6-a) to Comparative Example 8-a (C8-a), Comparative Example 9 (C9),pharmacokinetics in porcine ilio-femoral arteries was evaluated inaccording to the following procedure.

Example 9

Preparation of Drug Eluting Balloon

A balloon catheter (manufactured by Terumo Corp., the material of theballoon (dilation portion) is a nylon elastomer) having a size of adiameter 6.0×a length 40 mm (dilation portion) when dilated wasprepared.

Coating solution 2 was prepared. The coating solution 2 was coated onthe dilated balloon such that the solvent of the coating solution isslowly volatilized to make the amount of paclitaxel be about 3 μg/mm².

That is, the coating was performed as in the Example 2.

Comparative Example 6-a (C6-a)

Comparative Example 6-a (C6-a) in FIG. 10 and FIG. 11 is from the dataof IN.PACT®. The IN.PACT® data was presented by R. J. Melder, Sc. D. atLINC 2013 (IN.PACT DEB technology and Pre-clinical Science).

Comparative Example 7-a (C7-a)

Comparative Example 7-a (C7-a) in FIG. 10 and FIG. 11 is from the dataof Lutonix®. The Lutonix® data was presented by R. Virmani, MD at LINC2014 (Pre-clinical safety data and technology review).

Comparative Example 8-a (C8-a)

Comparative Example 8-a (C8-a) in FIG. 10 and FIG. 11 is from the dataof Cotavance®. The Cotavance® data was referred to in the literature(Cardiovascular Interventions, 6, 8, 2013, 883-890) and was presented byR. Virmani, MD (Pros and Cons of Different Technologies in PeripheralArteries: Insights from A Pathologist).

Comparative Example 9 (C9)

Comparative Example 9 (C9) in FIG. 10 and FIG. 11 is from the data ofFreeway®. The Freeway® data was presented by R. P. Strandmann at euroPCR 2013 (Effect of drug-coated balloon on porcine peripheral arteries:physiologic vascular function, safety and efficacy experiments).

1. Method

Twenty-four porcine animals were designated to pharmacokinetic study. Atthe treatment procedure, angiography was utilized to identify targettreatment sits within the iliofemoral and superficial femoral arteries

In the studies, two arteries (left and right iliofemoral arteries) wereused in each animal. Angiography was performed prior, during andpost-treatment to evaluate treatment and blood flow. After the drugeluting balloon treatment procedure has concluded, the animals wererecovered and allowed to reach the predetermined 1-hr and 1, 7, and 28days survival time point. A carotid artery cut down was performed and asheath was placed for vascular access. The target tissue was carefullydissected from surrounding tissue at 1-hr and at 1, 7, and 28 daysfollowing treatment with the drug eluting balloon. The paclitaxelconcentration measurement in tissue was performed by LC-MS/MS analysis.

2. Result

Pharmacokinetics in porcine femoral arteries was evaluated. FIG. 10 is agraph showing the AUC (area under the curve) of the drug on 0.02-0.04day (0.5-1 hour) to 7 day of Example 9 and of Comparative Examples C6 toC9 for the transfer in the porcine femoral arterial tissue. In FIG. 10,the horizontal axis represents Example or Comparative Examples, thenumber “9” means Example 9, and the numbers with letters, that is,“C6-a” to “C9” mean Comparative Example 6-a (C6-a), Comparative Example7-a (C7-a), Comparative Example 8-a (C8-a) and Comparative Example 9(C9). In addition, the vertical axis represents the AUC (ng·day/mg) ofdrug on 0.04 day to 7 day in the target arterial tissue.

The AUC of the drug on 0.04 day (1 hour) to 7 day in the target arterialtissue after the balloon dilation observed in Example 9 was 254ng·day/mg, which is higher than Comparative Example 6-a (C6-a),Comparative Example 7-a (C7-a), Comparative Example 8-a (C8-a) andComparative Example 9 (C9). In addition, FIG. 11 is a graph showing thepharmacokinetic profile up to 27±1 day of Example 9 and of ComparativeExamples C6 to C9 for the transfer in the porcine femoral arterialtissue. In FIG. 11, 9 is an Example and C6 to C9 are ComparativeExamples. The horizontal axis represents day(s) after dilation of thedrug eluting balloon. In addition, the vertical axis represents drugconcentration in the target arterial tissue.

The AUC of the drug on 0.04 day to 7 day obtained in Example 9 was thehighest compared to drug eluting balloons manufactured by others, whichwas referred to the literature, and the reduction rate of drug from 0.04day (1 hour) to 1 day was at most 50%. After 7 day, the drugconcentration in the tissue decreased to 2 ng/mg tissue by the 28 day.

The pharmacokinetic profile observed in Example 9 showed a high drugconcentration in the tissue by 7 day after dilation of the balloon, andafter that, it promptly cleared and maintained low concentration by day28. A high drug concentration in the tissue by 7 day affects smoothmuscle cell proliferation, after that prompt clearance from the tissuedoes not inhibit endothelial cell growth. So, drug eluting balloon asdescribed herein provides superior outcomes in both efficacy and safety.

I. Intravascular Stenosis Inhibitory Effect in a Porcine Coronary Artery

For the drug eluting balloon in Example 10 and Comparative Example 6-b(C6-b) to Comparative Example 8-b (C8-b), Comparative Example 10 (C10)to Comparative Example 11 (C11), intravascular stenosis inhibitoryeffect in a porcine coronary artery was evaluated in according to thefollowing procedure.

Example 10

Preparation of Drug Eluting Balloon

A balloon catheter (manufactured by Terumo Corp., the material of theballoon (dilation portion) is a nylon elastomer) having a size of adiameter 3.0×a length 20 mm (dilation portion) when dilated wasprepared. Coating solution 2 was prepared. The coating solution 2 wascoated on the dilated balloon such that the solvent of the coatingsolution is slowly volatilized to make the amount of paclitaxel be about3 μg/mm².

That is, the coating was performed as in the Example 2. ComparativeExamples 6-b (C6-b)

As drug eluting balloon of Comparative Example 6-b (C6-b) in FIG. 12,IN.PACT® (manufactured by INVAtec/Medtronic, Inc.) was provided. Theballoon catheter having a size of a diameter 3.0×a length 20 mm(dilation portion) when dilated was prepared.

Comparative Example 7-b (C7-b)

Comparative Example 7-b (C7-b) in FIG. 12 is from the data of Lutonix®.The Lutonix® data was presented by R. Virmani, MD (Pros and Cons ofDifferent Technologies in Peripheral Arteries: Insights from APathologist).

Comparative Example 8-b (C8-b)

Comparative Example 8-b (C8-b) in FIG. 12 is from the data of SeQuentPlease). The SeQuent® data was referred to in the literature (Thrombosisand Haemostasis, 105, 5, 2011, 864-872).

Comparative Example 10 (C10)

Comparative Example 10 (C10) in FIG. 12 is from the data of PanteraLux®. The Pantere® data was referred to in the literature (Thrombosisand Haemostasis, 105, 5, 2011, 864-872).

Comparative Example 11 (C11)

Comparative Example 11 (C11) in FIG. 12 is a non-drug coated balloon ofwhich the surface is not coated with a drug. A balloon catheter(manufactured by Terumo Corp., the material of the balloon (dilationportion) is a nylon elastomer) having a size of a diameter 3.0×a length20 mm (dilation portion) when dilated was prepared.

1. Method

(1) A guiding catheter with a guide wire was inserted by an 8 Fr sheath,and guided to the left and right coronary artery opening portion underX-ray fluoroscopy.

(2) Angiography of each coronary artery was performed (coronary artery:left anterior descending coronary artery (LAD), right coronary artery(RCA), and left circumflex coronary artery (LCX)), and a diameter ofcoronary artery obtained by angiography was measured by a QCA software.

(3) A site in which a diameter of a stent is 1.2 times, and a diameterof the drug eluting balloon is 1.3 times with respect to a diameter of ablood vessel was selected, and work after stent placement was performed.

(4) After a bare metal stent (BMS) having a diameter of 3 mm and alength 15 mm was dilated for 30 seconds in the selected coronary arteryis to give the diameter of the stent 1.2 times larger than the original,a balloon catheter for the stent placement was removed. At the stentplacement site, after the drug eluting balloon (balloon diameter 3mm×length 20 mm) having the drug coating layer prepared in Example 10and Comparative Example 6-b (C6-b) and a non-drug coated balloon inComparative Example 11 (C11) were dilated for 1 minute so as to be 1.3times with respect to the diameter of a blood vessel, the ballooncatheter was removed.

(5) After the drug eluting balloon was dilated, the guiding catheter andthe sheath were removed. After a central side of a carotid artery wasligated, a gap of dissected muscles of an incision opening of cervicalregion was sutured with a suture, and the skin was sutured by a surgicalstapler.

(6) 28 days after the balloon dilatation, autopsy was performed.

Calculation Method of Intravascular Stenosis Rate

An intravascular stenosis rate was calculated in according to thefollowing procedure.

Blood vessel images were taken by a Leica microscope and a pathologyimaging system. By these images, the internal area of an externalelastic lamina area, internal elastic lamina area, internal area oflumen, and internal area of stent were measured.

[Area Stenosis Rate (%) Calculation Method]Area stenosis rate (%) was calculated from “area stenosisrate=(neointimal area/internal elastic lamina area)×100”.2. Result

FIG. 12 is a graph showing percent area stenosis at 28 days of Example10 and of Comparative Examples C6-b to C8-b, C10 and C11 for theintravascular stenosis inhibitory effect in porcine coronary arteries.In FIG. 12, the horizontal axis represents Example or ComparativeExamples, the numbers “10” means Example 10, and the numbers withletters, that is, “C6-b” to “C8-b”, “C10” and “C11” mean ComparativeExample 6-b (C6-b), Comparative Example 7-b (C7-b), Comparative Example8-b (C8-b), Comparative Example 10 (C10) and Comparative Example 11(C11). In addition, the vertical axis represents percent area stenosisat 28 days.

In Comparative Example 11 (C11), area stenosis rate of a blood vesseltreated with the non-drug coated balloon as a non-drug treated controlwas 38.4%. The area stenosis rate of a blood vessel treated with thedrug eluting balloon in Example 10 was 16.8%, and a significant stenosisinhibitory effect was observed as compared to the non-drug treatedcontrol. On the other hand, the area stenosis rate of a blood vesseltreated with the commercially available drug eluting balloon (IN.PACT®)in Comparative Example 6-b (C6-b) was 30%. That is, the area stenosisrate of a blood vessel treated with the drug eluting balloon accordingto Example 10 showed a stronger effect than the IN.PACT® of ComparativeExample 6-b (C6-b) and any other drug eluting balloons which werereferred to the literature, and the most excellent stenosis inhibitoryeffect was obtained.

J. Morphological Evaluation in a Porcine Coronary Artery (Evaluation ofLocal Toxicity)

For the drug eluting balloon in Example 10 and a non-drug coated balloonin Comparative Example 11 (C11), morphological analysis of the treatedsections in a porcine coronary artery was performed as in evaluation oflocal toxicity on the blood vessel in according to the followingprocedure.

1. Method

(1) A guiding catheter with a guide wire was inserted by an 8 Fr sheath,and guided to the left and right coronary artery opening portion underX-ray fluoroscopy.

(2) Angiography of each coronary artery was performed (coronary artery:left anterior descending coronary artery (LAD), right coronary artery(RCA), and left circumflex coronary artery (LCX)), and a diameter ofcoronary artery obtained by angiography was measured by a QCA software.

(3) A site in which a diameter of the drug eluting balloon is 1.3 timeswith respect to a diameter of a blood vessel was selected, and procedurewas performed.

(4) After the drug eluting balloon (balloon diameter 3 mm×length 20 mm)having the drug coating layer prepared in Example 10 and a non-drugcoated balloon in Comparative Example 11 (C11) were dilated for 1 minuteso as to be 1.3 times with respect to the diameter of a blood vessel,the balloon catheter was removed.

(5) After the drug eluting balloon was dilated, the guiding catheter andthe sheath were removed. After a central side of a carotid artery wasligated, a gap of dissected muscles of an incision opening of cervicalregion was sutured with a suture, and the skin was sutured by a surgicalstapler.

(6) 28 days after the balloon dilatation, autopsy was performed.

[Injury Score Calculation Method, Injury Score]

Evaluation of injury score was performed in all circumferences of bloodvessel according to the method of Schwartz R S., et al. (Schwartz R S.,et al. Restenosis and the proportional neointimal response to coronaryartery injury: results in a porcine model. J Am Coll Cardiol. 1992,267-74).

The contents of injury score are as follows.

Score 0: Internal elastic lamina intact; endothelium typically denuded;media compressed but not lacerated.

Score 1: Internal elastic lamina lacerated; media typically compressedbut not lacerated.

Score 2: Internal elastic lacerated; media visibly lacerated: externalelastic lamina intact but compressed.

Score 3: External elastic lamina lacerated; typically large lacerationsof media extending through the external elastic lamina; coil wiressometimes residing in adventitia.

In addition, all the scores were obtained by calculating the averagevalue of the three locations, that is, a proximal location, a middlelocation, and a distal location of the stent placement sites for eachblood vessel.

[Inflammatory Score Calculation Method, Inflammatory Score]

Evaluation of inflammatory score was performed in all circumferences ofblood vessel according to the method of Kornowski R., et al. (KornowskiR., et al. In-stent restenosis: contributions of inflammatory responsesand arterial injury to neointimal hyperplasia. J Am Coll Cardiol. 1998,224-230).

The contents of inflammatory score are as follows.

Score 0: No inflammatory cells surrounding the strut.

Score 1: Light, noncircumferential lymphohistocytic infiltratesurrounding the strut.

Score 2: Localized, moderate to dense cellular aggregate surrounding thestrut noncircumferentially.

Score 3: Circumferential dense lymphohistiocytic cell infiltration ofthe strut.

In addition, all the scores were obtained by calculating the averagevalue of the three locations, that is, a proximal location (proximalportion), a middle location (middle portion), and a distal location(distal portion) of the stent placement sites for each blood vessel.

[Fibrin Content Calculation Method, Fibrin Content Score]

Evaluation of fibrin content was performed in all circumferences ofblood vessel according to the method of Radke, P. W. et. al (Radke, P.W. et. al Vascular effects of paclitaxel following drug-eluting balloonangioplasty in a porcine coronary model: the importance of excipients.Euro Intervention, 2011; 7, 730-737.

The content of the score of fibrin content is as follows.

Score 0: Fibrin localized in a blood vessel was not observed.

Score 1: Fibrin localized in a blood vessel was observed, or fibrin ismoderately deposited in a region less than 25% of all circumferences ofblood vessel observable near a strut of the stent.

Score 2: Fibrin is moderately deposited in a region greater than 25% ofall circumferences of blood vessel observable, or fibrin is heavilydeposited in a region less than 25% of all circumferences of bloodvessel observable between the struts and the proximity of the strut.

Score 3: Fibrin is severely deposited in a region greater than 25% ofall circumferences of blood vessel observable.

In addition, all the scores were obtained by calculating the averagevalue of the three locations, that is, a proximal location, a middlelocation, and a distal location of the stent placement sites for eachblood vessel.

[Endothelialization Score Calculation Method, Endothelialization Score]

The content of an endothelialization score is as follows.

Score 1: Up to 25% of all circumferences of vascular lumen observable iscovered with endothelial cells.

Score 2: 25% to 75% of all circumferences of vascular lumen observableis covered with endothelial cells.

Score 3: Equal to or greater than 75% of all circumferences of vascularlumen observable is covered with endothelial cells.

In addition, all the scores were calculated as an average value of threelocations, that is, a proximal, a middle and a distal location to thestent placement site, for each blood vessel.

2. Result

As the local toxicity of the treated sections in a porcine coronaryartery, injury score, inflammation score, fibrin content score andendothelialization score were observed. The results are shown in Table6. Moreover, the larger the number of the injury score is, the largerthe injury is, which is not preferable. The larger the number of theinflammation score is, the larger the inflammation, which is notpreferable. The larger the number of the fibrin content score is, thelarger the fibrin content is, which is not preferable. On the otherhand, the smaller the number of the endothelialization score is, theless the blood vessel is covered with the endothelial cells, which isnot preferable. In Table 6, 10 in a column of Examples/ComparativeExamples is an Example, and C11 is a Comparative Example.

The injury score, the inflammation score, the fibrin content score andendothelialization score of a blood vessel treated with the non-drugcoated balloon as a non-drug treated control in Comparative Example 11(C11) do not have an influence on the vascular remodeling since there isno effect (toxicity) by drugs, and the scores were 0.00±0.00, 0.00±0.00,1.00±0.00 and 3.00±0.00, respectively.

The injury score, the inflammation score, the fibrin content score andendothelialization score of a blood vessel treated with the drug elutingballoon according to Example 10 were 0.22±0.43, 0.29±0.48, 0.23±0.24 and2.89±0.28, respectively, and it was made clear that the local toxicityof the treated sections was the same as that of non-drug coated balloonin Comparative Example 11 (C11), that is, in spite that high stenosisinhibition effect was obtained, the local toxicity was extremely low.These results showed that DEB according to Example 10 had no influenceon the vascular remodeling, which reduce the risk of its latethrombosis. Although it strongly inhibits the stenosis, dualanti-platelet therapy (DAPT) expects to be limited for 4 weeks to thesame extent that non-drug coated balloon does.

TABLE 6 Examples/ Inflam- Fibrin Endothe- Comparative Injury mationcontent lialization Example score score score score 10 0.22 ± 0.43 0.29± 0.48 0.23 ± 0.24 2.89 ± 0.28 C11 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.003.00 ± 0.00

K. Uniform Stenosis Inhibitory Effect in a Porcine Coronary Artery

For the drug eluting balloon in Example 10, Comparative Example 6-b(C6-b) and Comparative Example 11 (C11), uniformity of intravascularstenosis inhibitory effect in a porcine coronary artery was evaluatedaccording to the following procedure.

1. Method

Evaluation of intravascular stenosis inhibitory effect in a porcinecoronary artery was performed as in evaluation of the Example 1. Allsegments were transected into three pieces, that is proximal portion,middle portion and distal portion, and area stenosis rate (%) ofsegment-to-segment was calculated by histomorphometric analysis.

2. Result

FIG. 13 is a graph showing uniformity of area stenosis rate (%) at 28days of Example 10, Comparative Examples C6-b and C11 for theintravascular stenosis inhibitory effect in porcine coronary arteries.In FIG. 13, the horizontal axis represents Example or ComparativeExamples, the number “10” means Example 10, and the numbers withletters, that is, “C6-b” and “C11” mean Comparative Example 6-b (C6-b)and Comparative Example 11 (C11). In addition, the vertical axisrepresents percent area stenosis of segment-to-segment at 28 days.

Drug eluting balloon according to Example 10 provided uniform inhibitoryeffects of vascular intima thickening in the treated lesion. On theother hand, effects of segment-to-segment in the lesion treated by thecommercially available drug eluting balloon (IN.PACT®) according toComparative Example 6-b (C6-b) were not uniform.

L. Uniformity of Drug Coating Layers on Balloon Surface

For the drug eluting balloon in Examples 10 to 13 and ComparativeExample 6-b (C6-b) and Comparative Example 12 (C12), uniformity of druglayers coated on surface of balloon was evaluated according to thefollowing procedure.

Example 11

Preparation of Drug Eluting Balloon

A balloon catheter (manufactured by Terumo Corp., the material of theballoon (dilation portion) is a nylon elastomer) having a size of adiameter 6.0×a length 100 mm (dilation portion) when dilated wasprepared.

Coating solution 2 was prepared. The coating solution 2 was coated onthe dilated balloon such that the solvent of the coating solution isslowly volatilized to make the amount of paclitaxel be about 3 μg/mm².

That is, the coating was performed as in the Example 2.

Example 12

Preparation of Drug Eluting Balloon

A balloon catheter (manufactured by Terumo Corp., the material of theballoon (dilation portion) is a nylon elastomer) having a size of adiameter 6.0×a length 200 mm (dilation portion) when dilated wasprepared.

Coating solution 2 was prepared. The coating solution 2 was coated onthe dilated balloon such that the solvent of the coating solution isslowly volatilized to make the amount of paclitaxel be about 3 μg/mm².

That is, the coating was performed as in the Example 2.

Example 13

Preparation of Drug Eluting Balloon

A balloon catheter (manufactured by Terumo Corp., the material of theballoon (dilation portion) is a nylon elastomer) having a size of adiameter 7.0×a length 200 mm (dilation portion) when dilated wasprepared.

Coating solution 2 was prepared. The coating solution 2 was coated onthe dilated balloon such that the solvent of the coating solution isslowly volatilized to make the amount of paclitaxel be about 3 μg/mm².

That is, the coating was performed as in the Example 2.

Comparative Example 12 (C12)

IN.PACT® (manufactured by INVAtec/Medtronic, Inc.) was provided. Theballoon having a size of a diameter 7.0×a length 120 mm (dilationportion) when dilated was prepared.

1. Method

For drug eluting balloons in Examples 11 to 13 and Comparative ExampleC12 (C12), that is having a size of a length 100 to 200 mm, uniformityanalysis of drug layers on balloon surface was performed by cutting into20 mm segments. On the other hand, drug eluting balloons in Example 10and Comparative Example C6-b (C6-b), that is having a size of a length20 mm, were cut into 6 or 7 mm segments. The paclitaxel content ofsegment-to-segment on balloon surface was measured by high performanceliquid chromatography.

2. Result

As the uniform evaluation of drug coating layers, the paclitaxel contentof segment-segment on balloon surface was analyzed. The results areshown in Table 7. In Table 7, “10” to “13” in a column ofExamples/Comparative Examples are Examples, and “C6-b” and “C12” areComparative Examples.

Drug eluting balloon having a size of a length 20 mm in Example 10 wascut into 6 or 7 mm segments, and then it showed relative standarddeviation (RSD %) of paclitaxel content of segment-to-segment was13.0(%). On the other hand, the drug eluting balloon having a size of alength 20 mm in Comparative Example C6-b (C6-b) was cut into 6 or 7 mmsegments in the same way, and then it showed relative standard deviation(RSD %) of paclitaxel content was 22.8%. That is, the drug elutingballoon as described herein has more uniform drug coating layers thanthat of Comparative Example C6-b.

In addition, drug elution balloon having a size of a length 100 to 200mm in Examples 11 to 13 was cut into 20 mm segments, and then relativestandard deviation (RSD %) of paclitaxel content of segment-to-segmentwas 1.0-3.4(%). On the other hand, the drug eluting balloon having asize of a length 120 mm in Comparative Example C12 (C12) was cut into 20mm segment in the same way, and then relative standard deviation (RSD %)of paclitaxel content was 25.3%. That is, it was showed that the drugeluting balloon as described herein has a uniform drug coating layerregardless of length of the balloon. In addition, it was showed the drugcoating layer is significant uniform compared to IN.PACT.

TABLE 7 Examples/ Comparative RSD Examples Balloon size (%) 10  ϕ3-20 mm13.0 11 ϕ6-100 mm 1.0 12 ϕ6-200 mm 3.4 13 ϕ7-200 mm 1.7 C6-b  ϕ3-20 mm22.8 C12  ϕ7-120 mm 25.3

M. Observation of Drug Coating Layer Uniformity of Drug Eluting Balloonby Scanning Electron Microscope (SEM)

For drug coating layer uniformity of drug eluting balloon in Example 10and Comparative Example 6-b (C6-b), paclitaxel crystals of drug coatinglayer was observed by scanning electron microscope (SEM).

1. Method

Observation of drug coating layer uniformity of drug eluting balloon byscanning electron microscope (SEM) was performed as in SEM images ofdrug eluting balloon in Examples 1 to 6 (FIGS. 1 to 6).

2. Result

As the uniformity of drug coating layers, paclitaxel crystals of drugcoating layer were observed. The SEM images shown in FIG. 14 and FIG. 15were obtained. FIG. 14 is SEM images of Example 10, and FIG. 15 is SEMimages of Comparative Example C6-b (C6-b).

FIG. 14, which is SEM images of Example 10, showed uniform paclitaxelmicro-crystals. In addition, it was shown that the paclitaxelmicro-crystals uniformity arranged and constantly sized in the drugcoating layer on the balloon surface. On the other hand, FIG. 15, whichis SEM images of Comparative Example C6-b (C6-b), showed non-uniformdrug coating layer. In addition, SEM images of FIG. 15, which is IN.PACTin Comparative Example C6-b (C6-b), showed that drug coating layer iscomposed of crystals and amorphous material.

N. Evaluation of Durability of Drug Coating Layer on Balloon Surface

For the drug eluting balloon in Examples 13, 14 and Comparative Example12 (C12), durability of drug coating layers on balloon surface wasevaluated according to the following procedure.

Example 14

Preparation of Drug Eluting Balloon

A balloon catheter (manufactured by Terumo Corp., the material of theballoon (dilation portion) is a nylon elastomer) having a size of adiameter 6.0×a length 40 mm (dilation portion) when dilated wasprepared.

Coating solution 2 was prepared. The coating solution 2 was coated onthe dilated balloon such that the solvent of the coating solution isslowly volatilized to make the amount of paclitaxel be about 3 μg/mm².

That is, the coating was performed as in the Example 2.

1. Method

To measure durability of drug coating layer during a process to bedelivered to the lesion of the treatment, the test was performed using asimulated peripheral model. The guiding sheath was filled with normalsaline and was set having an angle of about 45 degrees. And then, aguide wire was passed through the guiding sheath. During the test,normal saline in the guiding sheath was kept at 37° C. Drug elutingballoon was tracked over a guide wire for 1 minute until the balloonexited. After that, the residual paclitaxel content on balloon surfacewas measured by high performance liquid chromatography.

2. Result

As the durability evaluation of drug coating layers, residual paclitaxelcontent on balloon surface after the passage in a simulated peripheralmodel was measured. The results are shown in Table 8. In Table 8, “13”and “14” in a column of Examples/Comparative Examples are Examples, and“C12” is a Comparative Example.

After simulated use in wet vessel model, residual paclitaxel content onballoon surface of drug eluting balloon having a size of a length 40 mmin Example 14 was 84% (before inflation). In addition, residualpaclitaxel content on balloon surface of drug eluting balloon having asize of a length 200 mm in Example 13 was 84%. On the other hand,residual paclitaxel content of the IN.PACT having a size of a length 120mm in Comparative Example C12 (C12) was 63%. It was shown that the drugeluting balloon as described herein can deliver paclitaxel whileapplying uniform microcrystals to the entire treated lesion. Inaddition, the drug eluting balloon with long length can keep the uniformmicrocrystalline drug during delivering to the target lesion, too. Inother words, the distal portion, the middle portion, and the proximalportion of the drug eluting balloon were able to circumferentiallymaintain a uniform structure of the plurality of the regularly arrangedcrystals on the balloon after delivery to the lesion to be treated.Especially, the distal end (the distal portion) of the expandable member(balloon) is mostly slided or glided to other surfaces including thelumen of the medical devices like catheters, and the structure of theuniform crystalline particles on the balloon can easily come off.Therefore, the distal end of the expandable member as described hereinhas a drug coating layer which shows an inhibitory effects of vascularintima thickening.

Based on what has been described above, it was made clear that drugeluting balloon as described herein can deliver the uniform paclitaxelmicro-crystals without come-off (detachment or falling away) from theballoon surface during a process to be delivered to the lesion of thetreatment. That is, the drug eluting balloon as described herein can beexpanded in the lesion of the treatment while keeping the uniformity ofthe drug coating layer until dilated.

TABLE 8 Examples/ Residual paclitaxel content on the Comparative balloonsurface after the passage Example Balloon size in wet vessel model 14 ϕ6-40 mm 84% 13 ϕ7-200 mm 84% C12 ϕ7-120 mm 63%

O. Pharmacokinetics in Porcine Ilio-Femoral Arteries 2

For the drug eluting balloon in Example 9, Comparative Example 6-a(C6-a), Comparative Example 7-a (C7-a) and Comparative Example 13 (C13),pharmacokinetics in porcine iliofemoral arteries was evaluated accordingto the following procedure.

Comparative Example 13 (C13)

Comparative Example 13 (C13) in FIG. 16 and FIG. 17 is the Ranger™(manufactured by Boston Scientific) which is a paclitaxel-coated ballooncatheter. The Ranger™ results were disclosed on the web site by BostonScientific.

1. Method

Pharmacokinetics was performed as in the method of “H”.

The target tissue was carefully dissected from surrounding tissuefollowing treatment with the drug eluting balloon. The paclitaxelconcentration measurement in tissue was performed by LC-MS/MS analysis.

2. Result

Pharmacokinetics in porcine femoral arteries was evaluated. FIG. 16 is agraph showing the pharmacokinetic profile of Example 9, ComparativeExample 6-a (C6-a), Comparative Example 7-a (C7-a) and ComparativeExample 13 (C13) for the transfer in the porcine femoral arterialtissue. The horizontal axis represents day(s) after dilation of the drugeluting balloon. In addition, the vertical axis represents drugconcentration in the target arterial tissue. In FIG. 17, the horizontalaxis represents Example or Comparative Examples, the number “9” meansExample 9, and the numbers with letters, that is, “C6-a”, “C7-a”, and“C13” mean Comparative Example 6-a (C6-a), Comparative Example 7-a(C7-a) and Comparative Example 13 (C13), respectively. In addition, thevertical axis represents the AUC (ng·day/mg) of drug on 0.02 day to 7days in the target arterial tissue.

As illustrated in FIG. 16, the drug concentration in the target arterialtissue observed in Example 9 was 69.8, 53.4, 11.7, 4.0, and 2.3 ng/mgtissue on day 0.04, 1, 7, 21, and 28, respectively. On the other hand,the drug concentration in the target arterial tissue observed inComparative Example 6-a (C6-a) was 35, 7.7, 5.3, 11.1, and 1.5 ng/mgtissue on day 0.02, 1, 2, 7, and 26, respectively. The drugconcentration in the target arterial tissue observed in ComparativeExample 7-a (C7-a) was 58.9, 4.4, 2.2, and 1.6 ng/mg tissue on day 0.02,1, 7, and 28, respectively. The drug concentration in the targetarterial tissue observed in Comparative Example 13 (C13) was 48.8, 19.8,5.3, 1.9, and 0.4 ng/mg tissue on day 0.02, 1, 7, and 21, respectively.That is, the reduction rate of drug from 0.04 day (1 hour) to 1 day forExample 9 was at most 50%. On the other hand, the reduction rate of drugfrom 0.02-0.04 day (0.5-1 hour) to 1 day for Comparative Example 6-a(C6-a), Comparative Example 7-a (C7-a) and Comparative Example 13 (C13)was more than 50%.

FIG. 17 is a graph showing the AUC of the drug on 0.02-0.04 days (0.5-1hour) to 7 days of Examples 9, Comparative Example 6-a (C6-a),Comparative Example 7-a (C7-a) and Comparative Example 13 (C13) for thetransfer in the porcine femoral arterial tissue. In addition, thevertical axis represents the AUC (ng·day/mg) of drug on 0.02-0.04 day to7 day in the target arterial tissue.

The AUC of the drug on 0.04 day (1 hour) to 7 day in the target arterialtissue after the balloon dilation observed in Example 9 was 254ng·day/mg. On the other hand, the AUC of the drug on 0.02-0.04 day(0.5-1 hour) to 7 day in the target arterial tissue after the balloondilation observed in Comparative Example 6-a (C6-a), Comparative Example7-a (C7-a) and Comparative Example 13 (C13) was 69, 51, and 109ng·day/mg, respectively. That is, the AUC obtained in Example 9 washigher than 200 ng·day/mg. On the other hand, the AUC obtained inComparative Example 6-a (C6-a), Comparative Example 7-a (C7-a) andComparative Examples 13 (C13) was lower than 200 ng·day/mg. The AUCobtained in Example 9 is the highest.

As described herein, a high drug concentration in tissue by day 7 afterdilation of the balloon has an effect on smooth muscle cellproliferation. After that, prompt clearance from the tissue does notinhibit endothelial cell growth.

The detailed description above describes a drug coating layer disclosedby way of example. The invention is not limited, however, to the preciseembodiment and variations described. Various changes, modifications andequivalents can be employed by one skilled in the art without departingfrom the spirit and scope of the invention as defined in theaccompanying claims. It is expressly intended that all such changes,modifications and equivalents which fall within the scope of the claimsare embraced by the claims.

What is claimed is:
 1. A method of reducing the risk of embolization ofperipheral blood vessels, comprising: inserting a medical device intoone of the peripheral blood vessels, the medical device comprising apolyamide expandable member possessing a polyamide surface on which adrug coating layer is disposed, the drug coating layer being applied tothe polyamide surface of the polyamide expandable member by reverserotation in which the expandable member is rotated in an oppositedirection of dispensing the drug coating layer and in which the drugcoating layer is dispensed by a dispenser in contact with the polyamidesurface of the expandable member, the drug coating layer having acrystalline morphological form including a plurality of crystalparticles of a water-insoluble drug regularly arranged and uniformlysized on the polyamide surface of the polyamide expandable member, eachof the crystal particles being independently formed on the polyamidesurface of the polyamide expandable member, expanding the polyamideexpandable member, pressing the drug coating layer to a blood vesselwall of the peripheral blood vessel such that at least part of theplurality of crystal particles is transferred to the blood vessel wall,and deflating the polyamide expandable member such that generation ofmicroparticulates having a size that causes embolization of peripheralblood vessels is suppressed.
 2. The method of claim 1, wherein each ofthe plurality of crystal particles has an elongated body with alinearly-shaped long axis and forms an angle in a predetermined rangewith respect to the polyamide surface of the polyamide expandable memberwith which the long axis of the elongated body intersects.
 3. The methodof claim 2, wherein at least a vicinity of a distal end of the elongatedbody is hollow.
 4. The method of claim 2, wherein a cross-sectionalshape of the elongated body perpendicular to the long axis is a polygon.5. The method of claim 1, wherein the drug coating layer which has thecrystalline morphological form including the plurality of crystalparticles of water-insoluble drug comprises excipient particles formedof an excipient which are irregularly arranged between the crystalparticles; and wherein a molecular weight of the excipient is less thana molecular weight of the water-insoluble drug, a ratio occupied by theexcipient particles per a predetermined area of the substrate is lessthan a ratio occupied by the crystal particles, and the excipientparticles do not form a matrix.
 6. The method of claim 1, wherein thewater-insoluble drug is selected from a group consisting of paclitaxel,rapamycin, docetaxel, and everolimus.
 7. The method of claim 1, whereinmicroparticulates are generated in the blood vessels.
 8. The method ofclaim 7, wherein the microparticulates generated in the blood vesselshave a diameter of 10-25 μm.
 9. The method of claim 1, furthercomprising lowering a level of necrosis.
 10. The method of claim 1,further comprising lowering a risk of amputation.
 11. The method ofclaim 1, wherein the suppression of the generation of microparticulateshaving a size that causes embolization of peripheral blood vesselsincludes suppressing microparticulates of a diameter of 100 μm to 900μm.
 12. The method of claim 1, wherein the drug coating layer isdispensed by the dispenser while the dispenser translates along alongitudinal axis of the medical device at a speed of 0.01 mm/sec 2mm/sec.
 13. The method of claim 1, wherein the drug coating layer isdispensed on the polyamide surface of the expandable member at 0.01μL/sec 1.5 μL/sec.
 14. A method of reducing the risk of embolization ofperipheral blood vessels, comprising: inserting a medical device intoone of the peripheral blood vessels, the medical device comprising apolyamide expandable member possessing a polyamide surface on which adrug coating layer is disposed, the drug coating layer being applied tothe polyamide surface of the polyamide expandable member by reverserotation in which the expandable member is rotated in an oppositedirection of dispensing the drug coating layer and in which the drugcoating layer is dispensed by a dispenser in contact with the polyamidesurface of the expandable member, the drug coating layer having acrystalline morphological form and comprising: a plurality of crystalparticles of a water-insoluble drug; a solvent in which the plurality ofcrystal particles are dissolved, the solvent being comprised of waterand at least one of tetrahydrofuran and acetone; and excipient particlesformed of an excipient irregularly arranged between the crystalparticles, a molecular weight of the excipient being less than amolecular weight of the water-insoluble drug, the crystal particlesbeing regularly arranged and uniformly sized on the polyamide surface ofthe polyamide expandable member, each of the crystal particles beingindependently formed on the polyamide surface of the polyamideexpandable member, expanding the expandable member, pressing the drugcoating layer to a blood vessel wall such that at least part of theplurality of crystal particles is transferred to the blood vessel wall,and deflating the expandable member such that generation ofmicroparticulates having a size that causes embolization of peripheralblood vessels is suppressed.
 15. The method of claim 14, wherein each ofthe plurality of crystal particles is an elongated body and at least avicinity of a distal end of each elongated body is hollow.
 16. Themethod of claim 14, wherein each of the plurality of crystal particlesis an elongated body possessing a long axis, and a cross-sectional shapeof each elongated body perpendicular to the long axis is a polygon. 17.The method of claim 14, wherein the drug coating layer is dispensed bythe dispenser while the dispenser translates along a longitudinal axisof the medical device at a speed of 0.01 mm/sec-2 mm/sec.
 18. The methodof claim 14, wherein the drug coating layer is dispensed on thepolyamide surface of the expandable member at 0.01 μL/sec-1.5 μL/sec.19. A method of reducing the risk of embolization of peripheral bloodvessels, comprising: inserting a medical device into one of theperipheral blood vessels, the medical device comprising a polyamideexpandable member possessing a polyamide surface on which a drug coatinglayer is disposed, the drug coating layer being applied to the polyamidesurface of the polyamide expandable member by reverse rotation in whichthe expandable member is rotated in an opposite direction of dispensingthe drug coating layer and in which the drug coating layer is dispensedby a dispenser in contact with the polyamide surface of the expandablemember, the drug coating layer having a crystalline morphological formand comprising: a plurality of crystal particles of a water-insolubledrug; a solvent in which the plurality of crystal particles aredissolved, the solvent being comprised of water and at least one oftetrahydrofuran and acetone; and excipient particles formed of anexcipient irregularly arranged between the crystal particles, amolecular weight of the excipient being less than a molecular weight ofthe water-insoluble drug, the crystal particles of the water-insolubledrug each defining an elongated body, the elongated bodies forming thecrystal particles each possessing one end fixed to the polyamideexpandable member, the elongated bodies forming the crystal particlesbeing regularly arranged and uniformly sized on the polyamide surface ofthe polyamide expandable member, each of the elongated bodies formingthe crystal particles being independently formed on the polyamidesurface of the polyamide expandable member, each of the elongated bodiesforming the crystal particles possessing a long axis that intersects thepolyamide surface of the polyamide expandable member, expanding theexpandable member, pressing the drug coating layer to a blood vesselwall such that at least part of the plurality of crystal particles istransferred to the blood vessel wall, and deflating the expandablemember such that generation of microparticulates having a size thatcauses embolization of peripheral blood vessels is suppressed.
 20. Themethod of claim 19, wherein a vicinity of a distal end of each elongatedbody is hollow.
 21. The method of claim 19, wherein a cross-sectionalshape of each elongated body perpendicular to the long axis is apolygon.
 22. The method of claim 19, wherein the drug coating layer isdispensed by the dispenser while the dispenser translates along alongitudinal axis of the medical device at a speed of 0.01 mm/sec-2mm/sec.
 23. The method of claim 19, wherein the drug coating layer isdispensed on the polyamide surface of the expandable member at 0.01μL/sec-1.5 μL/sec.
 24. A method of reducing the risk of embolization ofperipheral blood vessels, comprising: inserting a medical device intoone of the peripheral blood vessels, the medical device comprising anexpandable member possessing a surface on which a drug coating layer isdisposed, the drug coating layer being applied to the surface of theexpandable member by reverse rotation in which the expandable member isrotated in an opposite direction of dispensing the drug coating layerand in which the drug coating layer is dispensed by a dispenser incontact with the surface of the expandable member, the drug coatinglayer having a crystalline morphological form including a plurality ofcrystal particles of a water-insoluble drug regularly arranged anduniformly sized on the surface of the expandable member, each of thecrystal particles being formed on the surface of the expandable member,expanding the expandable member, pressing the drug coating layer to ablood vessel wall of the peripheral blood vessel such that at least partof the plurality of crystal particles is transferred to the blood vesselwall, and deflating the expandable member such that generation ofmicroparticulates having a size that causes embolization of peripheralblood vessels is suppressed.
 25. The method of claim 24, wherein thedrug coating layer is dispensed by the dispenser while the dispensertranslates along a longitudinal axis of the medical device at a speed of0.01 mm/sec-2 mm/sec.
 26. The method of claim 24, wherein the drugcoating layer is dispensed on the surface of the expandable member at0.01 μL/sec-1.5 μL/sec.